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Prelims · Science & technology · 32 questions

Human body, health & diseases

Every UPSC Prelims question on this topic, 2016–2026, newest first. Tap an option to check yourself; the answer and explanation open below it.

Human body, health & diseases questions per year: 2016: 1, 2017: 1, 2018: 0, 2019: 2, 2020: 2, 2021: 3, 2022: 4, 2023: 2, 2024: 1, 2025: 0, 2026: 0 Asked in 8 of 11 years · most in 2022 (4)

Practising Science & technology? Take it as timed sets of 25 →

UPSC syllabus: “General Science.” Sub-topics in the detailed syllabus →

Showing 1–30 of 32, newest first.

Prelims 2025 · Q48

Easy

प्रायः समाचारों में चर्चित, एकक्लोनी प्रतिरक्षियों (मोनोक्लोनल ऐंटिबॉडी) के संदर्भ में, निम्नलिखित कथनों पर विचार कीजिए :

  1. I.वे मानव-निर्मित प्रोटीन हैं।
  2. II.वे विशिष्ट प्रतिजनों (एंटीजेन) से बंधन बनाने की अपनी क्षमता के कारण प्रतिरक्षात्मक प्रकार्य को उद्दीपित करते हैं।
  3. III.वे निपा विषाणु के संक्रमण जैसे विषाणु संक्रमणों के उपचार में प्रयुक्त होते हैं।

उपर्युक्त कथनों में कौन-कौन से सही हैं?

Read this question in English

With reference to monoclonal antibodies, often mentioned in news, consider the following statements:

I. They are man-made proteins.

II. They stimulate immunological function due to their ability to bind to specific antigens.

III. They are used in treating viral infections like that of Nipah virus.

Which of the statements given above are correct?

(a) I and II only · (b) II and III only · (c) I and III only · (d) I, II and III

उत्तर और व्याख्या · explanation in English

Answer: (d) I, II और III

All three statements are correct. Monoclonal antibodies are identical antibody proteins made in a laboratory, each locking on to one specific antigen, and one of them (m102.4) was kept ready in India to treat Nipah virus patients.

  • ✓ I They are antibodies, which are proteins, produced in the laboratory (for example from hybridoma cells), not by the patient's own body.
  • ✓ II Each one is designed to bind a single antigen with high precision, and that binding helps the immune system attack the target.
  • ✓ III The monoclonal antibody m102.4 was procured by ICMR for Nipah cases, and a facility to administer it was set up in Kerala during the 2019 outbreak.
  • • Since then WHO's fact sheet says there is no licensed specific treatment or vaccine for Nipah yet, so such antibodies are used on an emergency or experimental basis.

Remember · Monoclonal antibodies are lab-made, single-target antibody proteins; m102.4 is the one kept ready by ICMR against Nipah virus.

Sources

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q49

Easy

निम्नलिखित कथनों पर विचार कीजिए :

  1. I.महासागरी जल में कोई विषाणु जीवित नहीं बच सकता।
  2. II.कोई विषाणु, जीवाणुओं में संक्रमण नहीं कर सकता।
  3. III.कोई विषाणु, परपोषी कोशिका में कोशिकीय अनुलेखनात्मक सक्रियता को परिवर्तित नहीं कर सकता।

उपर्युक्त में से कितने कथन सही हैं?

Read this question in English

Consider the following statements:

I. No virus can survive in ocean waters.

II. No virus can infect bacteria.

III. No virus can change the cellular transcriptional activity in host cells.

How many of the statements given above are correct?

(a) Only one · (b) Only two · (c) All the three · (d) None

उत्तर और व्याख्या · explanation in English

Answer: (d) कोई भी नहीं

None of the statements is correct, because each one is an absolute claim ("no virus can...") and a single counter-example disproves it. Viruses are abundant in seawater, bacteriophages infect bacteria, and many viruses take over the host cell's gene activity.

  • ✗ I Viruses are the most abundant biological entities in the oceans, reaching up to about 10 crore (10^8) particles in every millilitre of seawater.
  • ✗ II Bacteriophages are viruses that infect bacteria. NCERT describes how a phage attaches to a bacterium and its genetic material enters the bacterial cell.
  • ✗ III An infected cell treats the viral genetic material as its own and makes more virus particles, so its gene activity is redirected. Many viruses actively shut off the host's own gene expression to help themselves multiply.

Remember · Viruses live in seawater, bacteriophages infect bacteria, and viruses reprogram host-cell gene activity, so 'no virus can...' statements are false.

📘 Read it in NCERT: Class 12 Biology, Ch 5 (practise this chapter) · Class 12 Biology, Ch 5 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2024 · Q33

Easy

निम्नलिखित में से कौन-सा, मानव शरीर में संश्लेषित होता है जो रक्त वाहिकाओं को विस्फारित करता है और रक्त प्रवाह को बढ़ाता है ?

Read this question in English

Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow?

(a) Nitric oxide · (b) Nitrous oxide · (c) Nitrogen dioxide · (d) Nitrogen pentoxide

उत्तर और व्याख्या · explanation in English

Answer: (a) नाइट्रिक ऑक्साइड

Nitric oxide (NO) is made by the cells lining our blood vessels (the endothelium). It diffuses into the surrounding smooth muscle and makes it relax, which widens the vessels and lets more blood flow; its discovery as a signalling molecule won the 1998 Nobel Prize in Physiology or Medicine.

  • ✓ (a) Furchgott, Ignarro and Murad showed that the 'endothelium-derived relaxing factor' that dilates blood vessels is nitric oxide; heart drugs such as nitroglycerin work by releasing NO.
  • ✗ (b) Nitrous oxide (N2O) is 'laughing gas', used as an anaesthetic and a greenhouse gas; the body does not make it to control blood vessels.
  • ✗ (c) Nitrogen dioxide (NO2) is a brown, toxic air pollutant from vehicle exhausts and combustion that irritates the lungs; it is not a body signal.

Remember · Nitric oxide (NO) = body's own vasodilator, made by the endothelium; 1998 Nobel (Furchgott, Ignarro, Murad). Nitroglycerin relieves angina by releasing NO. N2O = laughing gas.

📘 Read it in NCERT: Class 11 Fundamentals of Physical Geography, Ch 11 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2024 · Q99

Medium

‘प्रधानमंत्री सुरक्षित मातृत्व अभियान’ के संदर्भ में, निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.यह योजना किसी भी सरकारी स्वास्थ्य सुविधा केंद्र में गर्भावस्था की दूसरी और तीसरी तिमाही में महिलाओं को प्रसवपूर्व चिकित्सा देखभाल सेवाओं के लिए न्यूनतम पैकेज और प्रसवोत्तर छह महीने की स्वास्थ्य चिकित्सा देखभाल सेवा की गारंटी प्रदान करती है ।
  2. 2.इस योजना के अंतर्गत, कुछ विशिष्टताओं वाले निजी क्षेत्र के स्वास्थ्य देखभाल सेवा प्रदाता स्वेच्छा से नज़दीकी सरकारी स्वास्थ्य सुविधा केंद्रों में सेवाएँ प्रदान कर सकते हैं ।

उपर्युक्त कथनों में से कौन-सा/कौन-से सही है/हैं ?

Read this question in English

With reference to the ‘Pradhan Mantri Surakshit Matritva Abhiyan’, consider the following statements:

1. This scheme guarantees a minimum package of antenatal care services to women in their second and third trimesters of pregnancy and six months post-delivery health care service in any government health facility.

2. Under this scheme, private sector health care providers of certain specialities can volunteer to provide services at nearby government health facilities.

Which of the statements given above is/are correct?

(a) 1 only · (b) 2 only · (c) Both 1 and 2 · (d) Neither 1 nor 2

उत्तर और व्याख्या · explanation in English

Answer: (b) केवल 2

Only statement 2 is correct: PMSMA encourages private doctors to volunteer at government health facilities. Statement 1 goes wrong because PMSMA is an antenatal (before-birth) care programme run at designated government facilities; it has no six-month post-delivery package.

  • ✗ 1. PMSMA guarantees a minimum antenatal package for women in the 2nd/3rd trimesters at designated government facilities, on the 9th of every month. Post-delivery care for six months is not part of it, and it is not offered at any government facility.
  • ✓ 2. The programme has a systematic approach to engage the private sector, motivating private practitioners to volunteer for the campaign at government health facilities.

Remember · PMSMA (2016): free antenatal check-up on the 9th of every month for 2nd/3rd-trimester women at designated government facilities; private doctors volunteer.

Sources

  • About the scheme, Pradhan Mantri Surakshit Matritva Abhiyan (MoHFW) ↗ “PMSMA guarantees a minimum package of antenatal care services to women in their 2nd / 3rd trimesters of pregnancy at designated government health facilities … The programme follows a systematic approach for engagement with private sector which includes motivating private practitioners to volunteer for the campaign”

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2023 · Q16

X-Ray · Core #27 Easy

निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.कुछ छत्रकों (मशरूमों) में औषधीय गुण होते हैं।
  2. 2.कुछ छत्रकों में मनःप्रभावी (साइकोऐक्टिव) गुण होते हैं।
  3. 3.कुछ छत्रकों में कीटनाशी गुण होते हैं।
  4. 4.कुछ छत्रकों में जैव संदीप्तिशील (बायोल्युमिनिसेंट) गुण होते हैं।

उपर्युक्त में से कितने कथन सही हैं?

Read this question in English

Consider the following statements:

1. Some mushrooms have medicinal properties.

2. Some mushrooms have psychoactive properties.

3. Some mushrooms have insecticidal properties.

4. Some mushrooms have bioluminescent properties.

How many of the above statements are correct?

(a) Only one · (b) Only two · (c) Only three · (d) All four

उत्तर और व्याख्या · explanation in English

Answer: (d) सभी चार

Mushrooms are the fruiting bodies of a very diverse group of fungi, and each property in the list is shown by at least some species: medicine (reishi, turkey tail), mind-altering chemicals (psilocybin), insect-deterring proteins and compounds, and a natural glow.

  • ✓ 1. NCERT notes that wild edible mushrooms have high nutritional and medicinal values. Medicinal mushrooms such as reishi and turkey tail have been used against infections for centuries in Asia, and for over 30 years have been approved as an add-on to standard cancer treatment in Japan and China.
  • ✓ 2. Psilocybin, a hallucinogen found in certain mushrooms ("magic mushrooms"), alters perception, mood and thought.
  • ✓ 3. Some mushrooms are rarely attacked by insects; studies of their fruit bodies have found insecticidal proteins and antifeedant compounds that are being explored for pest control.
  • ✓ 4. Several gilled mushrooms glow in the dark through a luciferin–luciferase reaction.

Remember · Fungi, including mushrooms, give medicines (reishi), psychoactive psilocybin, insecticidal proteins and bioluminescence (luciferin–luciferase light).

📘 Read it in NCERT: Class 9 Exploration, Ch 12 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2023 · Q18

Easy

निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.कुछ सूक्ष्मजीव जल के क्वथनांक से ऊपर के तापमान वाले वातावरण में पनप सकते हैं।
  2. 2.कुछ सूक्ष्मजीव जल के हिमांक से नीचे के तापमान वाले वातावरण में पनप सकते हैं।
  3. 3.कुछ सूक्ष्मजीव 3 से कम pH वाले अत्यंत अम्लीय वातावरण में पनप सकते हैं।

उपर्युक्त में से कितने कथन सही हैं?

Read this question in English

Consider the following statements:

1. Some microorganisms can grow in environments with temperature above the boiling point of water.

2. Some microorganisms can grow in environments with temperature below the freezing point of water.

3. Some microorganisms can grow in highly acidic environment with a pH below 3.

How many of the above statements are correct?

(a) Only one · (b) Only two · (c) All three · (d) None

उत्तर और व्याख्या · explanation in English

Answer: (c) सभी तीन

Microbes live in places no other life can: hot vents, snow and ice, and strongly acidic sites. Such extremophiles (thermophiles, psychrophiles, acidophiles) make all three statements true.

  • ✓ 1. Hyperthermophiles thrive in hydrothermal vents. Under high pressure, the methanogen Methanopyrus kandleri strain 116 has multiplied at 122 °C in the laboratory, above water's normal boiling point of 100 °C.
  • ✓ 2. Cold-loving microbes (psychrophiles) live in permafrost, sea ice and under thick snow, where they stay active below 0 °C in films of salty, unfrozen water.
  • ✓ 3. Acidophiles grow in highly acidic places such as acid mine drainage and acidic hot springs; some archaea grow best at a pH below 1.

Remember · Extremophiles: thermophiles (up to 122 °C under pressure), psychrophiles (below 0 °C), acidophiles (pH < 3), halophiles (salt).

📘 Read it in NCERT: Class 12 Biology, Ch 8 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2023 · Q52

Medium

एनीमिया मुक्त भारत रणनीति के अंतर्गत की जा रही व्यवस्थाओं के संदर्भ में, निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.इसमें स्कूल जाने से पूर्व के (प्री-स्कूल) बच्चों, किशोरों और गर्भवती महिलाओं के लिए रोगनिरोधक कैल्सियम पूरकता प्रदान की जाती है।
  2. 2.इसमें शिशु जन्म के समय देरी से रज्जु बंद करने के लिए अभियान चलाया जाता है।
  3. 3.इसमें बच्चों और किशोरों की निर्धारित अवधियों पर कृमि-मुक्ति की जाती है।
  4. 4.इसमें मलेरिया, हीमोग्लोबिनोपैथी और फ्लुओरोसिस पर विशेष ध्यान देने के साथ स्थानिक बस्तियों में एनीमिया के गैर-पोषण कारणों की ओर ध्यान दिलाना शामिल है।

उपर्युक्त में से कितने कथन सही हैं?

Read this question in English

Consider the following statements in the context of interventions being undertaken under Anaemia Mukt Bharat Strategy:

1. It provides prophylactic calcium supplementation for pre-school children, adolescents and pregnant women.

2. It runs a campaign for delayed cord clamping at the time of childbirth.

3. It provides for periodic deworming to children and adolescents.

4. It addresses non-nutritional causes of anaemia in endemic pockets with special focus on malaria, hemoglobinopathies and fluorosis.

How many of the statements given above are correct?

(a) Only one · (b) Only two · (c) Only three · (d) All four

उत्तर और व्याख्या · explanation in English

Answer: (c) केवल तीन

Statements 2, 3 and 4 are correct; statement 1 is wrong. Anaemia Mukt Bharat supplies prophylactic iron and folic acid, not calcium, and adds deworming, a behaviour-change campaign that includes delayed cord clamping, and action on non-nutritional causes such as malaria, haemoglobinopathies and fluorosis.

  • ✗ 1. The first of the six interventions is prophylactic Iron Folic Acid supplementation (for example, 60 mg iron plus 500 mcg folic acid tablets for pregnant women). Calcium supplementation is not part of it.
  • ✓ 2. The year-round Behaviour Change Communication campaign includes promoting the practice of delayed cord clamping.
  • ✓ 3. Periodic deworming runs through National Deworming Day, with mass deworming of children and adolescents aged 1 to 19 years twice a year, on 10 February and 10 August.
  • ✓ 4. The strategy includes awareness, screening and treatment of non-nutritional causes of anaemia in endemic pockets, with special focus on malaria, haemoglobinopathies and fluorosis.

Remember · Anaemia Mukt Bharat's six interventions: iron-folic acid, deworming, behaviour-change (incl. delayed cord clamping), testing and treatment, fortified foods, non-nutritional causes. No calcium.

Sources

  • Anaemia Mukt Bharat, National Health Mission (MoHFW) ↗ “The six interventions under Anemia Mukt Bharat strategy are as follows: i) Prophylactic Iron Folic Acid Supplementation … c) Increase intake of iron-rich, protein-rich and vitamin C-rich foods; dietary diversification; food fortification; d) Promoting practice of delayed cord clamping. … Intensifying awareness, screening and treatment of non-nutritional causes of anaemia in endemic pockets, with special focus on malaria, haemoglobinopathies and fluorosis.”

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2023 · Q67

X-Ray · Core #25 Easy

‘वोलबैचिया पद्धति’ का कभी-कभी निम्नलिखित में से किस एक के संदर्भ में उल्लेख होता है?

Read this question in English

'Wolbachia method' is sometimes talked about with reference to which one of the following?

(a) Controlling the viral diseases spread by mosquitoes · (b) Converting crop residues into packing material · (c) Producing biodegradable plastics · (d) Producing biochar from thermochemical conversion of biomass

उत्तर और व्याख्या · explanation in English

Answer: (a) मच्छरों से होने वाले विषाणु रोगों के प्रसार को नियंत्रित करना

The Wolbachia method is used to control viral diseases spread by mosquitoes, mainly dengue. Wolbachia is a bacterium that lives naturally in many insects; when it is introduced into Aedes aegypti mosquitoes, they transmit dengue virus much less.

  • ✓ (a) Wolbachia has been transferred into Aedes aegypti mosquitoes and reduces their transmission of dengue virus. WHO's Vector Control Advisory Group has assessed the approach and confirmed its public health value for dengue control.
  • ✗ (b) Turning crop residue into packing material is a materials process and has nothing to do with a bacterium living inside insects.
  • ✗ (d) Biochar comes from heating biomass in a thermochemical process such as pyrolysis. It is not a mosquito-control method.

Remember · Wolbachia is an insect-dwelling bacterium. Released in Aedes aegypti mosquitoes, it cuts dengue transmission, so it is a mosquito-borne disease control method.

Sources

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2023 · Q70

X-Ray · Core #11 Medium

‘माइक्रोसैटेलाइट डी॰ एन॰ ए॰’ निम्नलिखित में से किस एक मामले में प्रयोग किया जाता है?

Read this question in English

'Microsatellite DNA' is used in the case of which one of the following?

(a) Studying the evolutionary relationships among various species of fauna · (b) Stimulating 'stem cells' to transform into diverse functional tissues · (c) Promoting clonal propagation of horticultural plants · (d) Assessing the efficacy of drugs by conducting series of drug trials in a population

उत्तर और व्याख्या · explanation in English

Answer: (a) प्राणिजात की विभिन्न जातियों के बीच विकासपरक संबंधों का अध्ययन करना

Microsatellite DNA is used to study genetic variation between individuals and populations, which is why it helps in tracing evolutionary relationships among species. Microsatellites are short DNA stretches repeated many times, and the number of repeats varies from one organism to another.

  • ✓ (a) Because repeat numbers in microsatellites differ so much between individuals and populations, they work as genetic markers. Comparing them shows how closely related organisms or populations are.
  • ✗ (b) Turning stem cells into different tissues is done with growth signals and culture conditions. It does not use microsatellite DNA.
  • ✗ (d) Drug trials in a population test how well a medicine works. Microsatellites do not assess drug efficacy.

Remember · Microsatellites are short repeated DNA stretches whose repeat number varies between individuals. They serve as genetic markers, for DNA fingerprinting and for studying relationships and diversity.

📘 Read it in NCERT: Class 12 Biology, Ch 5 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2022 · Q37

X-Ray · Core #25 Easy

निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.जैवपरत (बायोफिल्म) मानव ऊतकों के भीतर चिकित्सकीय अंतर्रोपों पर बन सकती हैं ।
  2. 2.जैवपरत खाद्यपदार्थ और खाद्य प्रसंस्करण सतहों पर बन सकती हैं ।
  3. 3.जैवपरत प्रतिजैविक प्रतिरोध दर्शा सकती हैं ।

उपर्युक्त कथनों में कौन-से सही हैं ?

Read this question in English

Consider the following statements:

1. Biofilms can form on medical implants within human tissues.

2. Biofilms can form on food and food processing surfaces.

3. Biofilms can exhibit antibiotic resistance.

Which of the statements given above are correct?

(a) 1 and 2 only · (b) 2 and 3 only · (c) 1 and 3 only · (d) 1, 2 and 3

उत्तर और व्याख्या · explanation in English

Answer: (d) 1, 2 और 3

All three statements are true. A biofilm is a community of microbes attached to a surface and wrapped in a protective matrix; it can grow on implants inside the body and on food and food-processing equipment, and the microbes in it survive antibiotics far better than free-floating ones.

  • ✓ 1. Biofilms form on medical implants and other devices in the body and cause serious chronic infections that are hard to clear.
  • ✓ 2. Food and food-processing surfaces give biofilms nutrients to grow on, which makes them a food-safety problem.
  • ✓ 3. The biofilm lifestyle makes bacteria more resistant to antibiotics and to the body's immune defences.

Remember · Biofilm = microbes stuck to a surface in a protective matrix. Found on implants and food surfaces; tolerates antibiotics, so infections turn chronic.

Sources

  • NIH National Library of Medicine (PMC), The Role of Bacterial Biofilm in Antibiotic Resistance and Food Contamination ↗ “Biofilm is a critical problem in the medical sector since it is formed on medical implants within human tissue and involved in a multitude of serious chronic infections. … Food and food processing surface become an ideal environment for biofilm formation where there are sufficient nutrients for microbial growth and attachment. … the biofilm phenotype that these bacteria adapt during device-associated infection facilitates increased resistance to antibiotics and host immune defenses”

Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2022 · Q38

Medium

प्रजैविकों (प्रोबायोटिक्स) के संदर्भ में निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.प्रजैविक, जीवाणु और यीस्ट दोनों के बने होते हैं ।
  2. 2.प्रजैविकों में जीव, खाए जाने वाले खाद्य में होते हैं किन्तु वे नैसर्गिक रूप से हमारी आहार-नली में नहीं पाए जाते ।
  3. 3.प्रजैविक दुग्ध शर्कराओं के पाचन में सहायक हैं ।

उपर्युक्त कथनों में कौन-सा/से सही है/हैं ?

Read this question in English

Consider the following statements in respect of probiotics:

1. Probiotics are made of both bacteria and yeast.

2. The organisms in probiotics are found in foods we ingest but they do not naturally occur in our gut.

3. Probiotics help in the digestion of milk sugars.

Which of the statements given above is/are correct?

(a) 1 only · (b) 2 only · (c) 1 and 3 · (d) 2 and 3

उत्तर और व्याख्या · explanation in English

Answer: (c) 1 और 3

Statements 1 and 3 are correct. Probiotics are live microbes, mostly bacteria but also some yeasts, and certain probiotic bacteria help digest lactose, the sugar in milk. Statement 2 is wrong because many probiotic organisms are the same as or similar to microbes that already live naturally in our body.

  • ✓ 1. Most probiotics are bacteria (Lactobacillus and Bifidobacterium are the commonest), but some are yeasts such as Saccharomyces boulardii.
  • ✗ 2. Many probiotic microbes are the same as or similar to those that naturally live in our bodies. NCERT too notes that lactic acid bacteria in our stomach help check disease-causing microbes.
  • ✓ 3. Probiotic bacteria that carry the enzyme beta-galactosidase help break down lactose. Yogurt cultures such as L. bulgaricus and S. thermophilus give a similar benefit to people who cannot digest milk sugar well.

Remember · Probiotics: live microbes, mostly bacteria (Lactobacillus, Bifidobacterium) plus some yeasts; they resemble our natural gut flora and can ease lactose digestion.

📘 Read it in NCERT: Class 12 Biology, Ch 8 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2022 · Q39

X-Ray · Core #25 Medium

कोविड-19 विश्वमहामारी को रोकने के लिए बनाई जा रही वैक्सीनों के प्रसंग में, निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.भारतीय सीरम संस्थान ने mRNA प्लेटफॉर्म का प्रयोग कर कोविशील्ड नामक कोविड-19 वैक्सीन निर्मित की ।
  2. 2.स्पुतनिक V वैक्सीन रोगवाहक (वेक्टर) आधारित प्लेटफॉर्म का प्रयोग कर बनाई गई है ।
  3. 3.कोवैक्सीन एक निष्कृत रोगजनक आधारित वैक्सीन है ।

उपर्युक्त कथनों में कौन-से सही हैं ?

Read this question in English

In the context of vaccines manufactured to prevent COVID-19 pandemic, consider the following statements:

1. The Serum Institute of India produced COVID-19 vaccine named Covishield using mRNA platform.

2. Sputnik V vaccine is manufactured using vector based platform.

3. COVAXIN is an inactivated pathogen based vaccine.

Which of the statements given above are correct?

(a) 1 and 2 only · (b) 2 and 3 only · (c) 1 and 3 only · (d) 1, 2 and 3

उत्तर और व्याख्या · explanation in English

Answer: (b) केवल 2 और 3

Statements 2 and 3 are correct. Sputnik V is a vector vaccine and COVAXIN is a whole-virus inactivated vaccine. Statement 1 is wrong because Covishield, made by the Serum Institute of India, is a viral-vector vaccine (adenovirus carrier), not an mRNA vaccine.

  • ✗ 1. Covishield is the Oxford-AstraZeneca vaccine produced in India by the Serum Institute. It uses a weakened chimpanzee adenovirus as a carrier, so it is a viral-vector vaccine. No mRNA is involved.
  • ✓ 2. Sputnik V (Gam-COVID-Vac) from Russia's Gamaleya Institute is a combined vector vaccine given in two components.
  • ✓ 3. COVAXIN by Bharat Biotech, developed with ICMR-NIV, uses a whole-virion inactivated Vero-cell platform: dead virus that cannot infect but still trains the immune system.

Remember · Covishield and Sputnik V: viral-vector vaccines. COVAXIN: inactivated whole virus. ZyCoV-D: DNA. mRNA is the Pfizer and Moderna type.

Sources

Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2022 · Q97

Easy

निम्नलिखित कथनों में कौन-सा एक, मानव शरीर में B कोशिकाओं और T कोशिकाओं की भूमिका का सर्वोत्तम वर्णन है ?

Read this question in English

Which one of the following statements best describes the role of B cells and T cells in the human body?

(a) They protect the body from environmental allergens. · (b) They alleviate the body's pain and inflammation. · (c) They act as immunosuppressants in the body. · (d) They protect the body from the diseases caused by pathogens.

उत्तर और व्याख्या · explanation in English

Answer: (d) वे शरीर को रोगजनकों द्वारा होने वाले रोगों से बचाती हैं ।

B cells and T cells are the two lymphocytes that run the body's specific immune response, so they protect us from diseases caused by pathogens (disease-causing microbes). B cells make antibodies; T cells help B cells make them.

  • ✓ (d) NCERT: immune responses are carried out by B-lymphocytes and T-lymphocytes. B cells produce antibodies against pathogens, and T cells help B cells produce them.
  • ✗ (a) An allergy is an exaggerated immune response to harmless substances in the environment such as pollen or mites. That reaction is the problem, not the protection.
  • ✗ (c) Immunosuppressants are drugs that damp down the immune system. B and T cells are what carry out the immune response.

Remember · B cells make antibodies against pathogens; T cells help B cells do so. Together they carry out the body's immune response, with memory of the first encounter.

📘 Read it in NCERT: Class 12 Biology, Ch 7 (practise this chapter) · Class 12 Biology, Ch 7 (practise this chapter) · Class 12 Biology, Ch 7 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2021 · Q25

X-Ray · Core #13 Hard

तंत्रिका अपह्रास (न्यूरोडीजेनेरेटिव) समस्याओं के लिए उत्तरदायी माने जाने वाले मैग्नेटाइट कण पर्यावरणीय प्रदूषकों के रूप में निम्नलिखित में से किनसे उत्पन्न होते हैं?

  1. 1.मोटरगाड़ी के ब्रेक
  2. 2.मोटरगाड़ी के इंजन
  3. 3.घरों में प्रयोग होने वाले माइक्रोवेव स्टोव
  4. 4.बिजली संयंत्र
  5. 5.टेलीफोन लाइन

नीचे दिए गए कूट का प्रयोग कर सही उत्तर चुनिए।

Read this question in English

Magnetite particles, suspected to cause neurodegenerative problems, are generated as environmental pollutants from which of the following?

1. Brakes of motor vehicles

2. Engines of motor vehicles

3. Microwave stoves within homes

4. Power plants

5. Telephone lines

Select the correct answer using the code given below.

(a) 1, 2, 3 and 5 only · (b) 1, 2 and 4 only · (c) 3, 4 and 5 only · (d) 1, 2, 3, 4 and 5

उत्तर और व्याख्या · explanation in English

Answer: (b) केवल 1, 2 और 4

Pollution-derived magnetite nanoparticles form when iron-bearing material is burnt or heated by friction, so they come from vehicle engine exhaust, brake wear and combustion at power stations. A 2016 study found such particles in human brain tissue and linked them to oxidative damage of the kind seen in Alzheimer's disease. Microwave ovens and telephone lines are not among the sources it names.

  • ✓ 1. Frictional heating of brake pads produces high-temperature magnetite nanoparticles at the roadside.
  • ✓ 2. Magnetite nanoparticles have been captured from the exhaust plume of diesel engines; combustion is the main source.
  • ✗ 3. The study names open fires and poorly sealed cooking or heating stoves as indoor sources of magnetite nanoparticles; microwave ovens are not among them.
  • ✓ 4. The study shows spherical, fused magnetite particles collected at a power station, an example of industrial combustion.
  • ✗ 5. Telephone lines are not among the sources the study names; they carry electrical signals, not iron-oxide particles from combustion or friction.

Remember · Airborne magnetite nanoparticles come from combustion and friction: vehicle exhaust, brake wear, power plants, open fires. They have been found in human brain tissue.

Sources

  • Maher et al., 'Magnetite pollution nanoparticles in the human brain', PNAS (2016), via PubMed Central ↗ “Frictional heating, e.g., of brake pads, can also produce high-temperature magnetite nanoparticles … TEM image of magnetite nanoparticles captured from the exhaust plume of a diesel engine. … Spherical magnetite particles, Didcot power station, comprising fused magnetite particles … Because enhanced ROS production is causally linked to neurodegenerative diseases such as Alzheimer’s disease, exposure to such airborne PM-derived magnetite nanoparticles might need to be examined as a possible hazard to human health.”

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2021 · Q65

X-Ray · Core #11 Medium

‘पुनःसंयोजित (रीकॉम्बिनेंट) वेक्टर वैक्सीन’ से संबंधित हाल के विकास के संदर्भ में, निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.इन वैक्सीनों के विकास में आनुवंशिक इंजीनियरी का प्रयोग किया जाता है।
  2. 2.जीवाणुओं और विषाणुओं का प्रयोग रोगवाहक (वेक्टर) के रूप में किया जाता है।

उपर्युक्त कथनों में से कौन-सा/कौन-से सही है/हैं?

Read this question in English

With reference to recent developments regarding ‘Recombinant Vector Vaccines’, consider the following statements:

1. Genetic engineering is applied in the development of these vaccines.

2. Bacteria and viruses are used as vectors.

Which of the statements given above is/are correct?

(a) 1 only · (b) 2 only · (c) Both 1 and 2 · (d) Neither 1 nor 2

उत्तर और व्याख्या · explanation in English

Answer: (c) 1 और 2 दोनों

Both statements are correct: a recombinant vector vaccine is built by genetic engineering, and the carrier (vector) that delivers the disease-causing agent's gene into our cells is a harmless virus or bacterium.

  • ✓ 1. Recombinant DNA technology lets scientists make a pathogen's antigen in bacteria or yeast, as with the hepatitis B vaccine from yeast. Recombinant vector vaccines rest on the same gene-splicing methods.
  • ✓ 2. NIAID, part of the US National Institutes of Health, describes recombinant vector vaccines as those that use a harmless virus or bacterium as a vector, or carrier, to introduce genetic material into cells. Covishield is a vectored vaccine that uses a virus as the carrier.

Remember · Recombinant vector vaccine = genetic engineering plus a harmless virus or bacterium as the carrier that delivers the pathogen's gene into our cells.

📘 Read it in NCERT: Class 12 Biology, Ch 7 (practise this chapter) · Class 12 Biology, Ch 9 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2021 · Q66

Medium

आनुवंशिक रोगों के संदर्भ में, निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.अंडों के अंतःपात्र (इन विट्रो) निषेचन से या तो पहले या बाद में सूत्रकणिका प्रतिस्थापन (माइटोकॉन्ड्रिअल रिप्लेसमेंट) चिकित्सा द्वारा सूत्रकणिका रोगों (माइटोकॉन्ड्रिअल डिजीज) को माता-पिता से संतान में जाने से रोका जा सकता है।
  2. 2.किसी संतान में सूत्रकणिका रोग आनुवंशिक रूप से पूर्णतः माता से जाता है न कि पिता से।

उपर्युक्त कथनों में से कौन-सा/कौन-से सही है/हैं?

Read this question in English

In the context of hereditary diseases, consider the following statements:

1. Passing on mitochondrial diseases from parent to child can be prevented by mitochondrial replacement therapy either before or after in vitro fertilization of egg.

2. A child inherits mitochondrial diseases entirely from mother and not from father.

Which of the statements given above is/are correct?

(a) 1 only · (b) 2 only · (c) Both 1 and 2 · (d) Neither 1 nor 2

उत्तर और व्याख्या · explanation in English

Answer: (c) 1 और 2 दोनों

Both statements are correct: mitochondrial DNA comes only from the mother's egg, and mitochondrial replacement therapy swaps the faulty mitochondria either before fertilisation (spindle transfer) or after it (pronuclear transfer).

  • ✓ 1. Two techniques are used: in maternal spindle transfer the mother's nuclear genetic material is moved into a donor egg before fertilisation, and in pronuclear transfer the fertilised embryo's nuclear material is moved into a donor embryo after fertilisation. Either way the child gets healthy donor mitochondria.
  • ✓ 2. Only egg cells contribute mitochondria to the embryo, so only females pass on mitochondrial DNA variants; a father's sperm does not pass them on.

Remember · Mitochondrial DNA is inherited only from the mother. Mitochondrial replacement therapy: spindle transfer (before fertilisation) or pronuclear transfer (after fertilisation).

Sources

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2021 · Q69

Easy

निम्नलिखित पर विचार कीजिए :

  1. 1.जीवाणु
  2. 2.कवक
  3. 3.विषाणु

उपर्युक्त में से किन्हें कृत्रिम/संश्लेषित माध्यम में संवर्धित किया जा सकता है?

Read this question in English

Consider the following:

1. Bacteria

2. Fungi

3. Virus

Which of the above can be cultured in artificial/synthetic medium?

(a) 1 and 2 only · (b) 2 and 3 only · (c) 1 and 3 only · (d) 1, 2 and 3

उत्तर और व्याख्या · explanation in English

Answer: (a) केवल 1 और 2

Bacteria and fungi are living cells that can feed and multiply on a lab-made nutrient medium, so they can be cultured in it. A virus has no cell machinery of its own and multiplies only inside a living host cell, so it cannot grow in a cell-free artificial medium.

  • ✓ 1. Bacteria grow as visible colonies on nutrient-rich gel or broth in a petri dish.
  • ✓ 2. Fungi also grow as colonies in a petri dish on a suitable nutrient medium.
  • ✗ 3. Viruses are acellular and multiply only after entering a living cell. To grow them, labs use living cells (cell culture, or fertilised eggs), not a synthetic medium.

Remember · Bacteria and fungi grow on artificial nutrient media; viruses need living host cells, so they cannot be cultured on a synthetic medium alone.

📘 Read it in NCERT: Class 12 Biology, Ch 8 (practise this chapter) · Class 8 Curiosity, Ch 2 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2021 · Q70

Medium

निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.एडीनोवायरसों में एकल-तंतु डी॰ एन॰ ए॰ संजीन (जीनोम) होते हैं, जबकि रेट्रोवायरसों में द्वि-तंतु डी॰ एन॰ ए॰ संजीन (जीनोम) होते हैं।
  2. 2.कभी-कभी सामान्य जुकाम एडीनोवायरस के कारण होता है, जबकि एड्स (ए॰ आइ॰ डी॰ एस॰) रेट्रोवायरस के कारण होता है।

उपर्युक्त कथनों में से कौन-सा/कौन-से सही है/हैं?

Read this question in English

Consider the following statements:

1. Adenoviruses have single-stranded DNA genomes whereas retroviruses have double-stranded DNA genomes.

2. Common cold is sometime caused by an adenovirus whereas AIDS is caused by a retrovirus.

Which of the statements given above is/are correct?

(a) 1 only · (b) 2 only · (c) Both 1 and 2 · (d) Neither 1 nor 2

उत्तर और व्याख्या · explanation in English

Answer: (b) केवल 2

Statement 2 is correct: adenoviruses can cause cold-like illness, and AIDS is caused by HIV, which is a retrovirus. Statement 1 is wrong on both counts, because adenoviruses have double-stranded DNA genomes, while retroviruses carry an RNA genome.

  • ✗ 1. Adenoviruses are non-enveloped viruses with double-stranded DNA, not single-stranded DNA. Retroviruses, such as HIV, have an RNA genome (later copied into DNA inside the host cell), not a double-stranded DNA genome.
  • ✓ 2. Adenoviruses cause respiratory infections, including mild cold-like illness. AIDS is caused by the Human Immunodeficiency Virus (HIV), a retrovirus.

Remember · Adenovirus: double-stranded DNA, respiratory infections. Retrovirus (HIV, cause of AIDS): RNA genome.

📘 Read it in NCERT: Class 12 Biology, Ch 7 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2021 · Q73

X-Ray · Core #25 Easy

‘ACE2’ पद का उल्लेख किस संदर्भ में किया जाता है?

Read this question in English

The term ‘ACE2’ is talked about in the context of

(a) genes introduced in the genetically modified plants · (b) development of India’s own satellite navigation system · (c) radio collars for wildlife tracking · (d) spread of viral diseases

उत्तर और व्याख्या · explanation in English

Answer: (d) विषाणुजनित रोगों का प्रसार

ACE2, short for angiotensin-converting enzyme 2, sits on the outer surface of human cells, and the spike of SARS-CoV-2 (the virus behind COVID-19) latches onto it to get inside. So it was discussed in the context of how a viral disease spreads.

  • ✓ (d) The spike protein of SARS-CoV-2 binds to ACE2 on host cells, which lets the virus enter them. The earlier SARS coronavirus used the same receptor.
  • ✗ (a) ACE2 is a human protein, not a gene introduced into genetically modified plants.
  • ✗ (b) India's own satellite navigation system is NavIC; ACE2 has nothing to do with navigation or radio collars.

Remember · ACE2 is the human cell-surface receptor that SARS-CoV-2 (and SARS-CoV) binds to for entry into cells.

Sources

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2021 · Q75

X-Ray · Core #60 Easy

निम्नलिखित में से किसमें ‘ट्राइक्लोसन’ के विद्यमान होने की सर्वाधिक संभावना है, जिसके लंबे समय तक उच्च स्तर के प्रभावन में रहने को हानिकारक माना जाता है?

Read this question in English

‘Triclosan’, considered harmful when exposed to high levels for a long time, is most likely present in which of the following?

(a) Food preservatives · (b) Fruit-ripening substances · (c) Reused plastic containers · (d) Toiletries

उत्तर और व्याख्या · explanation in English

Answer: (d) प्रसाधन सामग्री

Triclosan is an antibacterial chemical added to personal-care products such as some soaps, skin cleansers, deodorants and toothpastes, which are toiletries. It is a suspected endocrine (hormone-system) disruptor, so long exposure to high levels is a worry.

  • ✓ (d) The US FDA says triclosan is added to some antibacterial soaps and body washes, toothpastes and cosmetics, all toiletries. Some short-term animal studies link high doses to lower levels of some thyroid hormones, which is why long exposure is a concern.
  • ✗ (a) Food preservatives keep food from spoiling; triclosan is not a permitted food preservative. It is an antibacterial for personal-care products.
  • ✗ (b) Fruit-ripening substances are chemicals that release ethylene, the ripening hormone of plants. Triclosan is not a ripening agent.
  • ✗ (c) Triclosan is mainly an antibacterial added to personal-care products. The usual worry about reused plastic containers is a different one: chemicals such as BPA leaching out of the plastic.

Remember · Triclosan is an antibacterial agent in toiletries (soaps, toothpaste, deodorants) and a suspected endocrine disruptor.

Sources

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2020 · Q37

Medium

मानव प्रजनन तकनीकी में अभिनव प्रगति के संदर्भ में, “प्राक्केन्द्रिक स्थानान्तरण” (Pronuclear Transfer) का प्रयोग किस लिए होता है ?

Read this question in English

In the context of recent advances in human reproductive technology, "Pronuclear Transfer" is used for

(a) fertilization of egg in vitro by the donor sperm · (b) genetic modification of sperm producing cells · (c) development of stem cells into functional embryos · (d) prevention of mitochondrial diseases in offspring

उत्तर और व्याख्या · explanation in English

Answer: (d) संतान में सूत्रकणिका वाले रोगों का निरोध

Pronuclear transfer is a form of mitochondrial donation, used to stop a mother from passing a serious mitochondrial disease to her child. The nuclear DNA of her fertilised egg is moved into a donor egg that has healthy mitochondria, so the baby gets the parents' genes but the donor's healthy mitochondria.

  • ✗ (a) Fertilising an egg in the lab with donor sperm is ordinary IVF. Pronuclear transfer is an extra step done on embryos, not a way of fertilising an egg.
  • ✗ (b) The technique does not modify sperm-producing cells or edit genes; it swaps whole nuclear material between embryos.
  • ✗ (c) It does not turn stem cells into embryos. It moves the nuclear genetic material of one embryo into another embryo whose own nucleus has been removed.
  • ✓ (d) Mitochondrial donation treatment lets people with severe mitochondrial disease avoid passing it to their children. Pronuclear transfer is one of the two approved techniques, the other being maternal spindle transfer.

Remember · Pronuclear transfer = swap the nuclear DNA of an embryo into a donor embryo with healthy mitochondria, to prevent mitochondrial disease.

Sources

Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2020 · Q45

X-Ray · Core #25 Easy

भारत में न्यूमोकोकल संयुग्मी वैक्सीन (Pneumococcal Conjugate Vaccine) के उपयोग का क्या महत्त्व है ?

  1. 1.ये वैक्सीन न्यूमोनिया और साथ ही तानिकाशोथ और सेप्सिस के विरुद्ध प्रभावी हैं ।
  2. 2.उन प्रतिजैविकियों पर निर्भरता कम की जा सकती है जो औषध-प्रतिरोधी जीवाणुओं के विरुद्ध प्रभावी नहीं हैं ।
  3. 3.इन वैक्सीन के कोई गौण प्रभाव (side effects) नहीं हैं और न ही ये वैक्सीन कोई प्रत्यूर्जता सम्बन्धी अभिक्रियाएँ (allergic reactions) करती हैं ।

नीचे दिए गए कूट का प्रयोग कर सही उत्तर चुनिए :

Read this question in English

What is the importance of using Pneumococcal Conjugate Vaccines in India?

1. These vaccines are effective against pneumonia as well as meningitis and sepsis.

2. Dependence on antibiotics that are not effective against drug-resistant bacteria can be reduced.

3. These vaccines have no side effects and cause no allergic reactions.

Select the correct answer using the code given below:

(a) 1 only · (b) 1 and 2 only · (c) 3 only · (d) 1, 2 and 3

उत्तर और व्याख्या · explanation in English

Answer: (b) केवल 1 और 2

Pneumococcal conjugate vaccines (PCVs) protect against the diseases caused by the pneumococcus bacterium, chiefly pneumonia, meningitis and blood infection (sepsis), and fewer infections mean less reliance on antibiotics against resistant strains. No vaccine is free of side effects, so the claim in statement 3 is too absolute.

  • ✓ 1. The Health Ministry says PCV protects children against severe pneumococcal disease such as pneumonia and meningitis. Pneumococcus (Streptococcus pneumoniae) also causes blood infection (sepsis), and the vaccine greatly reduced this burden where it was introduced.
  • ✓ 2. After PCVs were introduced across the world, the share of pneumococci resistant to first-line antibiotics for pneumonia fell. Fewer infections and less resistance mean less dependence on failing antibiotics.
  • ✗ 3. WHO's vaccine safety notes list mild reactions, such as swelling, redness, tenderness and fever, and say severe allergic reactions are very rare, not absent.

Remember · PCV prevents pneumonia, meningitis and sepsis and helps check antibiotic resistance, but every vaccine can have mild side effects and, rarely, allergy.

Sources

Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2020 · Q47

Easy

निम्नलिखित कथनों में से कौन-से पादप और प्राणि कोशिकाओं के बीच सामान्य अंतर के बारे में सही हैं ?

  1. 1.पादप कोशिकाओं में सेलुलोस कोशिका भित्तियाँ होती हैं जबकि प्राणि कोशिकाओं में वे नहीं होतीं ।
  2. 2.पादप कोशिकाओं में प्लैज़्मा झिल्ली नहीं होती जबकि इसके विपरीत प्राणि कोशिकाओं में वे होती हैं ।
  3. 3.परिपक्व पादप कोशिका में एक बृहत् रसधानी होती है जबकि प्राणि कोशिका में अनेक छोटी रसधानियाँ होती हैं ।

नीचे दिए गए कूट का प्रयोग कर सही उत्तर चुनिए :

Read this question in English

Which of the following statements are correct regarding the general difference between plant and animal cells?

1. Plant cells have cellulose cell walls whilst animal cells do not.

2. Plant cells do not have plasma membrane unlike animal cells which do.

3. Mature plant cell has one large vacuole whilst animal cell has many small vacuoles.

Select the correct answer using the code given below:

(a) 1 and 2 only · (b) 2 and 3 only · (c) 1 and 3 only · (d) 1, 2 and 3

उत्तर और व्याख्या · explanation in English

Answer: (c) केवल 1 और 3

A plant cell has a cellulose cell wall and, when mature, usually one large central vacuole, while an animal cell has no cell wall and only small vacuoles, if any. Statement 2 is wrong because every cell, plant or animal, is enclosed by a plasma membrane.

  • ✓ 1. The plant cell wall is made mainly of cellulose. Animal cells lack a rigid cell wall, which lets them change shape easily.
  • ✗ 2. The plasma membrane (cell membrane) is the universal boundary of a cell. Plant cells have it too, just inside the cell wall.
  • ✓ 3. A mature plant cell usually has one large central vacuole filled with cell sap. Animal cells may have vacuoles, but they are not as large.

Remember · Cell wall (cellulose) and one big central vacuole belong to plant cells. The plasma membrane is present in all cells.

📘 Read it in NCERT: Class 9 Exploration, Ch 2 (practise this chapter) · Class 9 Exploration, Ch 2 (practise this chapter) · Class 9 Exploration, Ch 2 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2020 · Q48

Medium

निम्नलिखित में से कौन-से कारण/कारक बेंज़ीन प्रदूषण उत्पन्न करते हैं ?

  1. 1.स्वचालित वाहन (automobile) द्वारा निष्कासित पदार्थ
  2. 2.तम्बाकू का धुआँ
  3. 3.लकड़ी का जलना
  4. 4.रोगन किए गए लकड़ी के फर्नीचर का उपयोग
  5. 5.पॉलियूरिथेन से निर्मित उत्पादों का उपयोग

नीचे दिए गए कूट का प्रयोग कर सही उत्तर चुनिए :

Read this question in English

Which of the following are the reasons/factors for exposure to benzene pollution?

1. Automobile exhaust

2. Tobacco smoke

3. Wood burning

4. Using varnished wooden furniture

5. Using products made of polyurethane

Select the correct answer using the code given below:

(a) 1, 2 and 3 only · (b) 2 and 4 only · (c) 1, 3 and 4 only · (d) 1, 2, 3, 4 and 5

उत्तर और व्याख्या · explanation in English

Answer: (a) केवल 1, 2 और 3

Benzene is a volatile chemical released when fuels and other organic material burn, so vehicle exhaust, tobacco smoke and wood burning are all recognised sources of exposure. Varnished wooden furniture and polyurethane products are not named in the official lists of benzene sources.

  • ✓ 1. Benzene is present in motor vehicle exhaust and in petrol (gasoline) vapour.
  • ✓ 2. Tobacco smoke contains benzene, and WHO calls active and passive smoke exposure a significant source of exposure.
  • ✓ 3. Wood-burning fires are named among the common sources of benzene in air.
  • ✗ 4. UPSC's key does not count this as a benzene source. EPA's summary names glues, paints and furniture wax among household sources, but not varnished wooden furniture itself.
  • ✗ 5. Polyurethane products are not named among the recognised benzene sources in the EPA and WHO summaries, and UPSC's key does not count them.

Remember · Benzene comes from burning and fuels: vehicle exhaust, tobacco smoke, wood-burning fires, petrol vapour, and some glues and paints.

Sources

  • US EPA, Benzene TEACH Chemical Summary ↗ “Benzene is an organic compound found most often in air as a result of emissions from burning coal and oil, gasoline vapors at gasoline service stations, motor vehicle exhaust, cigarette smoke, wood-burning fires, some adhesives, and other sources … Sources include cigarette smoke; exhaust from motor vehicles; smoke from wood burning fires; and some household products which contain petroleum-based chemicals such as glues, paints, furniture wax, and lubricants.”
  • WHO, Exposure to benzene: a major public health concern ↗ “Active and passive exposure to tobacco smoke is also a significant source of exposure.”

Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2019 · Q95

X-Ray · Core #43 Easy

परिधेय प्रौद्योगिकी (विअरेबल टेक्नोलॉजि) के संदर्भ में, परिधेय उपकरणों द्वारा निम्नलिखित में से कौन-सा/से कार्य निष्पन्न किया जा सकता है/किए जा सकते हैं?

  1. 1.किसी व्यक्ति का अवस्थान (लोकेशन) निर्धारण
  2. 2.किसी व्यक्ति का निद्रा मॉनीटरन
  3. 3.श्रवण दोषयुक्त व्यक्ति की सहायता

नीचे दिए गए कूट का प्रयोग कर सही उत्तर चुनिए।

Read this question in English

In the context of wearable technology, which of the following tasks is/are accomplished by wearable devices?

1. Location identification of a person

2. Sleep monitoring of a person

3. Assisting the hearing impaired person

Select the correct answer using the code given below.

(a) 1 only · (b) 2 and 3 only · (c) 3 only · (d) 1, 2 and 3

उत्तर और व्याख्या · explanation in English

Answer: (d) 1, 2 और 3

All three tasks are done by wearable devices. Wrist-worn trackers and watches with GPS locate the wearer, their motion sensors estimate sleep patterns, and worn hearing aids help people with hearing loss.

  • ✓ 1. WHO describes global positioning system locators that track the location of the wearer, used for example to find people with dementia who wander. Some fitness wearables also carry a built-in GPS receiver that records position, speed and altitude.
  • ✓ 2. WHO notes that wrist- or hip-worn accelerometers give continuous data on physical activity and potentially sleep; accelerometer-based fitness wearables can estimate sleep patterns, along with steps and energy use.
  • ✓ 3. Hearing aids are among the assistive products WHO prioritises to mitigate hearing loss, and they are worn on or in the ear, so wearable devices can assist the hearing impaired.

Remember · Wearables include GPS trackers (location), fitness bands and watches (sleep, activity) and hearing aids: all three tasks are covered.

Sources

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2019 · Q98

X-Ray · Core #25 Medium

निम्नलिखित में से कौन-से, भारत में सूक्ष्मजैविक रोगजनकों में बहु-औषध प्रतिरोध के होने के कारण हैं?

  1. 1.कुछ व्यक्तियों में आनुवंशिक पूर्ववृत्ति (जेनेटिक प्रीडिस्पोजीशन) का होना
  2. 2.रोगों के उपचार के लिए प्रतिजैविकों (ऐंटिबॉयोटिक्स) की गलत खुराकें लेना
  3. 3.पशुधन फार्मिंग में प्रतिजैविकों का इस्तेमाल करना
  4. 4.कुछ व्यक्तियों में चिरकालिक रोगों की बहुलता होना

नीचे दिए गए कूट का प्रयोग कर सही उत्तर चुनिए।

Read this question in English

Which of the following are the reasons for the occurrence of multi-drug resistance in microbial pathogens in India?

1. Genetic predisposition of some people

2. Taking incorrect doses of antibiotics to cure diseases

3. Using antibiotics in livestock farming

4. Multiple chronic diseases in some people

Select the correct answer using the code given below.

(a) 1 and 2 · (b) 2 and 3 only · (c) 1, 3 and 4 · (d) 2, 3 and 4

उत्तर और व्याख्या · explanation in English

Answer: (b) केवल 2 और 3

Multi-drug resistance builds up when disease-causing microbes are repeatedly exposed to antibiotics they can survive, so wrong use of antibiotics in people and in farm animals is the cause. A patient's genes or other illnesses do not make a microbe resistant.

  • ✗ 1. Resistance is a trait of the microbe, not of the patient. It spreads when misused antibiotics let the hardiest microbes survive and multiply; a person's genetic make-up plays no part in that.
  • ✓ 2. Wrong doses, or stopping a course early, leave part of the bacterial population alive to multiply. WHO names the misuse and overuse of antimicrobials as the driver of drug-resistant pathogens.
  • ✓ 3. Antibiotics given to food-producing animals expose bacteria on farms to the same drugs. India's animal husbandry department has advised all States and Union Territories to stop the use of antibiotics in animal feed for this reason.
  • ✗ 4. Long-term illnesses may mean more infections and more medicines, but it is the misuse of antibiotics, not the patient's other disease, that produces resistant microbes.

Remember · Antimicrobial resistance is created by misuse and overuse of antibiotics, in humans and in animals. It is a property of the microbe, not of the patient.

Sources

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2019 · Q100

X-Ray · Core #25 Medium

निम्नलिखित में से कौन-सा एक कथन सही नहीं है?

Read this question in English

Which one of the following statements is not correct?

(a) Hepatitis B virus is transmitted much like HIV. · (b) Hepatitis B, unlike Hepatitis C, does not have a vaccine. · (c) Globally, the number of people infected with Hepatitis B and C viruses are several times more than those infected with HIV. · (d) Some of those infected with Hepatitis B and C viruses do not show the symptoms for many years.

उत्तर और व्याख्या · explanation in English

Answer: (b) यकृतशोथ C का टीका होता है, जबकि यकृतशोथ B का कोई टीका नहीं होता।

Statement (b) is the false one: hepatitis B has a safe and effective vaccine, usually given soon after birth, whereas it is hepatitis C that has no vaccine.

  • ✗ (a) This statement is true, so it is not the answer. Both viruses pass on through blood and other body fluids, for example through unsafe injections, sex with an infected partner and from mother to child.
  • ✓ (b) This is the statement that is not correct, so it is the answer. Hepatitis B can be prevented by a vaccine. NCERT Class 12 Biology notes that the hepatitis B vaccine is produced from yeast. Hepatitis C has no vaccine, but antiviral medicines can cure it.
  • ✗ (c) This statement is true. WHO puts chronic hepatitis B at 240 million and chronic hepatitis C at 47 million people, against about 41 million people living with HIV.
  • ✗ (d) This statement is true. Most people newly infected with hepatitis B have no symptoms, and chronic hepatitis C often stays silent for decades until the liver is damaged.
  • • Since then The figures above are the latest WHO estimates (2024-25), not the 2019 numbers; the gap between hepatitis B and C infections and HIV infections is still several-fold.

Remember · Hepatitis B has a vaccine; hepatitis C does not. Both spread through blood and body fluids, and both can stay silent for years.

Sources

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2018 · Q99

Easy

निम्नलिखित पर विचार कीजिए :

  1. 1.पक्षी
  2. 2.उड़ती धूल
  3. 3.वर्षा
  4. 4.बहती हवा

उपर्युक्त में से कौन-से पादप रोग फैलाते हैं ?

Read this question in English

Consider the following:

1. Birds

2. Dust blowing

3. Rain

4. Wind blowing

Which of the above spread plant diseases?

(a) 1 and 3 only · (b) 3 and 4 only · (c) 1, 2 and 4 only · (d) 1, 2, 3 and 4

उत्तर और व्याख्या · explanation in English

Answer: (d) 1, 2, 3 और 4

All four spread plant diseases. Most plant pathogens travel as spores or bacteria, and these are carried by wind, blown dust, splashing rain and even by birds.

  • ✓ 1. Spores stick to birds' feathers and beaks and are dropped on other plants. Chestnut blight spores, for example, are spread by many bird species, and powdery mildew fruiting bodies are carried on feathers.
  • ✓ 2. Dust is lifted soil, and soil is a recognised carrier of fungal spores. Blowing dust moves them from diseased fields to healthy ones.
  • ✓ 3. Rain splash and running water carry spores and bacteria from an infected leaf to healthy plant surfaces.
  • ✓ 4. Wind brings the first spores from neighbouring fields or far away, and then spreads the secondary infection from plant to plant.

Remember · Plant pathogens are dispersed by wind, water (rain), dust or soil, insects and birds. Every listed agent can spread plant diseases.

Sources

Question and answer: UPSC's official GS Paper I (2018, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2017 · Q31

X-Ray · Core #25 Easy

निम्नलिखित कथनों पर विचार कीजिए :

  1. 1.उष्णकटिबंधीय प्रदेशों में, ज़ीका वाइरस रोग उसी मच्छर द्वारा संचरित होता है जिससे डेंगू संचरित होता है ।
  2. 2.ज़ीका वाइरस रोग का लैंगिक संचरण होना संभव है ।

उपर्युक्त कथनों में से कौन-सा/से सही है/हैं ?

Read this question in English

Consider the following statements:

1. In tropical regions, Zika virus disease is transmitted by the same mosquito that transmits dengue.

2. Sexual transmission of Zika virus disease is possible.

Which of the statements given above is/are correct?

(a) 1 only · (b) 2 only · (c) Both 1 and 2 · (d) Neither 1 nor 2

उत्तर और व्याख्या · explanation in English

Answer: (c) 1 और 2 दोनों

Zika is spread mainly by Aedes mosquitoes (chiefly Aedes aegypti), the same day-biting mosquitoes that carry dengue and chikungunya, and WHO confirms that it can also pass through sexual contact. Both statements are correct.

  • ✓ 1. Aedes aegypti and Aedes albopictus carry Zika as well as dengue, chikungunya and urban yellow fever; these mosquitoes are most common in tropical and subtropical regions.
  • ✓ 2. Besides mosquito bites, Zika spreads from mother to fetus in pregnancy, through sexual contact, blood transfusion and laboratory exposure.

Remember · Zika: flavivirus spread by Aedes aegypti (also dengue, chikungunya vector); also sexual and mother-to-fetus transmission; infection in pregnancy can cause microcephaly.

Sources

  • WHO fact sheet: Zika virus ↗ “mainly Aedes aegypti but also Aedes albopictus ; these species also transmit dengue, chikungunya and urban yellow fever. These mosquitoes are most abundant in tropical and subtropical regions … Zika virus is also transmitted from mother to fetus during pregnancy, as well as through sexual contact, laboratory exposure, transfusion of blood and blood products”

Question and answer: UPSC's official GS Paper I (2017, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2016 · Q32

X-Ray · Core #7 Easy

भारत सरकार द्वारा चलाया गया ‘मिशन इंद्रधनुष’ किससे संबंधित है?

Read this question in English

'Mission Indradhanush' launched by the Government of India pertains to

(a) immunization of children and pregnant women · (b) construction of smart cities across the country · (c) India's own search for the Earth-like planets in outer space · (d) New Educational Policy

उत्तर और व्याख्या · explanation in English

Answer: (a) बच्चों और गर्भवती महिलाओं का प्रतिरक्षण

Mission Indradhanush is the Health Ministry's catch-up vaccination drive, launched in December 2014 under the Universal Immunization Programme. It targets districts and pockets where many children are unvaccinated or partly vaccinated, and also vaccinates pregnant women, with the aim of raising full immunisation coverage of children to 90%.

  • ✓ (a) In its first three phases the mission reached more than 2.1 crore children and also vaccinated 55.9 lakh pregnant women against tetanus (MoHFW).
  • ✗ (b) Urban development of 100 cities is the Smart Cities Mission (2015) of the Ministry of Housing and Urban Affairs.
  • ✗ (c) Indradhanush ('rainbow') refers to the several vaccine-preventable diseases the drive targets; it has no link to astronomy or exoplanet searches.

Remember · Mission Indradhanush (December 2014, MoHFW): intensified vaccination of unvaccinated/partly vaccinated children and pregnant women in low-coverage areas; goal of 90% full immunisation.

Sources

Question and answer: UPSC's official GS Paper I (2016, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

The Syllabus X-Ray of this topic

1 of its 5 sub-topics is Core

1 Core · 2 High · 0 Steady · 2 Rare

  • Core #25Diseases, vaccines & immunity · 8 questions
  • HighHuman body, nutrition & genetics basics · 4 questions
  • HighMicrobes, viruses & antimicrobial resistance · 3 questions

The X-Ray ranks all 928 sub-topics of the UPSC syllabus by what UPSC has asked since 2016. The 60 Prelims Core sub-topics are behind 51% of Prelims questions.

See the whole X-Ray →

The same topic in Mains

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