Test yourself

Biology

Class 12 · Science & Environment

Ch 7 · Human Health and Disease

Real UPSC Prelims questions from 2016–2026, linked to this book. Try each one first, then open the answer. 2026 answers follow UPSC's provisional answer key.

Prelims 2019 · Q100

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.

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UPSC's answer: (b)

NCERT answers it: Class 12 Biology, Ch 7 (Human Health and Disease).

Class 12 Biology, ch 7: a hepatitis B vaccine is produced from yeast. So (b), which says hepatitis B has no vaccine, is the incorrect statement. Answer (b).

Beyond NCERT: it is hepatitis C that has no vaccine; antiviral medicines can cure it. Source: WHO fact sheet, Hepatitis C, who.int

Hindi version: UPSC's official question paper (2019), question 100 ↗

Prelims 2021 · Q65

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

Show answer

UPSC's answer: (c)

NCERT answers it: Class 12 Biology, Ch 7 (Human Health and Disease); Class 12 Biology, Ch 9 (Biotechnology: Principles and Processes).

How to solve it with NCERT: Class 12 Biology, ch 7: recombinant DNA technology makes pathogens' antigen proteins in bacteria or yeast for vaccines — genetic engineering (1). Ch 9: Agrobacterium, a bacterium, and disarmed retroviruses are used as vectors to deliver genes (2). Answer (c).

Beyond NCERT: a recombinant vector vaccine uses a harmless virus or bacterium as a carrier (vector) to take a disease-causing agent's genetic material into our cells. Source: NIAID (US National Institutes of Health), 'Vaccine Types', niaid.nih.gov (content last reviewed July 2019)

Hindi version: UPSC's official question paper (2021), question 65 ↗

Prelims 2021 · Q70

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

Show answer

UPSC's answer: (b)

NCERT answers it: Class 12 Biology, Ch 8 (Microbes in Human Welfare); Class 12 Biology, Ch 7 (Human Health and Disease).

Class 12 Biology: retroviruses have an RNA genome (ch 7), so 1 is false. Adenovirus causes respiratory infections (ch 8), and HIV, which causes AIDS, is a retrovirus (ch 7), so 2 is true. Answer (b).

Beyond NCERT: adenoviruses in fact have double-stranded DNA genomes, while retroviruses carry RNA. So statement 1 gets both viruses wrong. Source: Gu et al., 'Molecular characterization and evolutionary analysis of human adenovirus type 55', Virus Genes (2025), on PubMed Central (US National Library of Medicine), PMC12263808

Hindi version: UPSC's official question paper (2021), question 70 ↗

Prelims 2022 · Q97

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.

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UPSC's answer: (d)

NCERT answers it: Class 12 Biology, Ch 7 (Human Health and Disease).

Class 12 Biology, ch 7: our immune responses are carried out by B-lymphocytes and T-lymphocytes; B-lymphocytes produce antibodies against pathogens, helped by T-cells. So they protect the body from diseases caused by pathogens. Answer (d).

Hindi version: UPSC's official question paper (2022), question 97 ↗

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