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.

Asked in 8 of 11 years · most in 2022 (4)

UPSC syllabus: “General Science.” See the full syllabus →

Prelims 2023 · Q16

Easy

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?

Answer & explanation

Answer: (d) All four

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

NCERT Class 9 · Exploration, Chapter 12 “Wild edible mushrooms are a valuable dietary food with high nutritional and medicinal values.”
US National Cancer Institute, Medicinal Mushrooms (PDQ), Patient Version ↗ “Medicinal mushrooms are mushrooms that are used as medicine. They have been used to treat infection for hundreds of years, mostly in Asia. … For more than 30 years, medicinal mushrooms have been approved as an addition to standard cancer treatments in Japan and China.”
US National Institute on Drug Abuse, Psilocybin (Magic Mushrooms) ↗ “Psilocybin is a chemical in certain types of mushrooms that grow on nearly every continent.”
Berestetskiy & Hu (2021), The Chemical Ecology Approach to Reveal Fungal Metabolites for Arthropod Pest Management, Microorganisms (PMC) ↗ “Mushrooms were found to be promising producers of antifeedant compounds as well as insecticidal proteins.”
Silva-Filho et al. (2023), Eoscyphella luciurceolata gen. and sp. nov., Journal of Fungi (PMC) ↗ “Some species of gilled mushroom are well known and stand out for their natural light emission with a luciferin/luciferase chemical reaction”

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

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?

Answer & explanation

Answer: (c) All three

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

NCERT Class 12 · Biology, Chapter 8 “sites such as deep inside the geysers (thermal vents) where the temperature may be as high as 1000C, deep in the soil, under the layers of snow several metres thick, and in highly acidic environments.”
Takai et al. (2008), Cell proliferation at 122°C by a hyperthermophilic methanogen, PNAS 105(31) (PMC) ↗ “Elevated hydrostatic pressures extend the temperature maximum for possible cell proliferation from 116°C at 0.4 MPa to 122°C at 20 MPa, providing the potential for growth even at 122°C under an in situ high pressure.”

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

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?

Answer & explanation

Answer: (c) Only three

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

Easy

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

Answer & explanation

Answer: (a) Controlling the viral diseases spread by mosquitoes

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

Call for public consultation: Target Product Profiles for Wolbachia infected Aedes aegypti population replacement intervention (World Health Organization) ↗ “Wolbachia, a symbiotic bacterium that occurs naturally in many insects, has been successfully transferred into the Aedes aegypti mosquito and has been found to reduce the transmission of the dengue virus.”

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

Medium

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

Answer & explanation

Answer: (a) Studying the evolutionary relationships among various species of fauna

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

NCERT Class 12 · Biology, Chapter 5 “These sequence show high degree of polymorphism and form the basis of DNA fingerprinting.”
Microsatellite, Talking Glossary of Genomic and Genetic Terms (National Human Genome Research Institute, US NIH) ↗ “The number of repeated segments within a microsatellite sequence often varies among people, which makes them useful as polymorphic markers for studying inheritance patterns in families or for creating a DNA fingerprint from crime scene samples.”

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 ·

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Human body, health & diseases

Prelims 2023 · Q16

Prelims 2023 · Q18

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Prelims 2023 · Q70

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