Human Health and Disease is a Class 12 Zoology chapter in the NEET (UG) syllabus. NEET720 has 1,260 reviewed practice questions on it, each with a quick answer and a step-by-step explanation. The 8 questions below are free and fixed, so you can bookmark this page; the full chapter, plus mistake tracking and spaced revision, is in the app.
206
easy
892
medium
162
hard
Topics covered
Common Human Diseases · Immunity · AIDS and Cancer · Drugs and Alcohol Abuse · Malaria · Amoebiasis · Ascariasis · Filariasis · Typhoid · Ringworm · Common Diseases in Humans · Autoimmunity · Innate and Acquired Immunity · Human Genetic Disorders · Blood Groups · Common Infectious Diseases · Immune System Disorders · HIV/AIDS · Allergy · Disease-causing organisms · Numerical - Epidemiology · Vaccination · Pneumonia · Vector-borne viral disease · Health and disease · Pneumonia vs common cold · Drug and Alcohol Abuse · Infectious Diseases · Substance Abuse · AIDS · Cancer · Common Diseases · Immunity and Cancer · Immunity and AIDS · Cancer and Immunity · Common Diseases and Immunity · Bacterial disease · Immune system · Drugs and Immunity · Disease and Public Health
8 free Human Health and Disease practice questions with answers
Choose an answer in your head before opening it. Each explanation says why the correct option is right and, where relevant, why the tempting wrong option is wrong.
Question 1 · easy · AIDS and Cancer
AIDS (Acquired Immuno Deficiency Syndrome) is caused by infection with which of the following?
- A.Human Immunodeficiency Virus (HIV), a retrovirus
- B.Human Papilloma Virus (HPV), a DNA virus
- C.Hepatitis B Virus (HBV)
- D.Epstein-Barr Virus (EBV)
Show answer and explanation
Answer: A. Human Immunodeficiency Virus (HIV), a retrovirus
AIDS is caused by the Human Immunodeficiency Virus (HIV), a retrovirus with an RNA genome.
HIV is a retrovirus, meaning its genome is RNA rather than DNA, and it uses the enzyme reverse transcriptase to convert its RNA into DNA inside the host cell. HPV, HBV, and EBV are all real pathogens associated with other diseases (cervical cancer, hepatitis, Burkitt's lymphoma respectively) but none of them cause AIDS.
Common mistake: Confusing HIV with other viruses that also cause serious human disease.
Key point: AIDS = caused by HIV, a retrovirus with RNA genome.
Question 2 · medium · AIDS and Cancer
HIV is classified as a retrovirus primarily because of which structural/functional feature?
- A.Its genome is double-stranded DNA that integrates directly into host chromosomes
- B.Its genome is RNA, and it carries reverse transcriptase to synthesise DNA from this RNA template
- C.It replicates exclusively inside red blood cells using host ribosomes
- D.It lacks a genome entirely and relies only on host enzymes for replication
Show answer and explanation
Answer: B. Its genome is RNA, and it carries reverse transcriptase to synthesise DNA from this RNA template
HIV is a retrovirus because its genetic material is RNA, and it uses reverse transcriptase to make a DNA copy of this RNA inside the host cell.
The defining feature of a retrovirus is the 'reverse' flow of genetic information: RNA to DNA (opposite to the usual DNA to RNA flow), catalysed by the viral enzyme reverse transcriptase. HIV's RNA genome is reverse-transcribed into viral DNA once inside a host macrophage/T-cell, and this DNA is then integrated into the host genome. Option A wrongly states the genome itself is DNA. Option C invents an RBC-based mechanism (HIV does not infect RBCs, which lack nuclei). Option D is biologically impossible since all viruses require a genome.
Common mistake: Thinking retroviruses have a DNA genome because the final integrated form is DNA.
Key point: Retrovirus = RNA genome + reverse transcriptase makes DNA copy.
Question 3 · easy · AIDS and Cancer
Statement I: HIV can be transmitted from an infected mother to her child through the placenta. Statement II: HIV can be transmitted through mosquito bites in areas with a high number of HIV-positive individuals. In light of the above statements, choose the correct answer.
- A.Both Statement I and Statement II are true
- B.Statement I is true but Statement II is false
- C.Statement I is false but Statement II is true
- D.Both Statement I and Statement II are false
Show answer and explanation
Answer: B. Statement I is true but Statement II is false
Placental transmission from mother to child is a recognised HIV transmission route; mosquito bites do not transmit HIV.
Statement I is TRUE: NCERT lists transmission from infected mother to child through the placenta as one of the established routes. Statement II is FALSE: HIV is not transmitted by mosquitoes, because the virus does not replicate within the mosquito and is not injected back into a new host the way the malarial parasite is; HIV transmission requires direct exchange of body fluids like blood, semen, or vaginal secretions.
Common mistake: Assuming any blood-feeding insect can transmit any blood-borne virus.
Key point: Mother-to-child (placental) transmission is real; mosquito transmission of HIV is a myth.
Question 4 · easy · AIDS and Cancer
Which of the following is NOT a recognised transmission route of HIV, as per NCERT?
- A.Transfusion of contaminated blood or blood products
- B.Sharing infected needles, as seen in intravenous drug abusers
- C.Sexual contact with an infected person
- D.Sharing food or water with an infected person
Show answer and explanation
Answer: D. Sharing food or water with an infected person
HIV does not spread by sharing food or water; the recognised routes involve exchange of body fluids like blood or semen.
NCERT lists four recognised transmission routes for HIV: sexual contact with an infected person, transfusion of contaminated blood/blood products, sharing infected needles (e.g., intravenous drug abusers), and mother-to-child transmission through the placenta. Sharing food or water does not transmit HIV because the virus requires direct exchange of specific body fluids and cannot survive or transmit through such casual routes.
Common mistake: Listing casual contact as a transmission route alongside genuine ones.
Key point: HIV needs body-fluid exchange to transmit; food/water sharing is not a route.
Question 5 · medium · AIDS and Cancer
The progressive decrease in the number of which immune cell type, caused by HIV infection, is directly responsible for the immune collapse seen in AIDS?
- A.B-lymphocytes
- B.Cytotoxic T-lymphocytes only
- C.Natural killer cells
- D.Helper T-lymphocytes (CD4+ cells)
Show answer and explanation
Answer: D. Helper T-lymphocytes (CD4+ cells)
HIV progressively decreases the number of helper T-lymphocytes (CD4+ cells), weakening the immune system.
HIV specifically infects and destroys helper T-lymphocytes, which bear the CD4 receptor that the virus uses to enter the cell. As new HIV particles are produced within infected macrophages and helper T-cells, the number of functional helper T-cells falls progressively. Since helper T-cells coordinate both humoral (B-cell) and cell-mediated immune responses, their depletion cripples the entire immune system, leaving the person susceptible to opportunistic infections that define AIDS.
Common mistake: Confusing helper T-cells with B-cells or cytotoxic T-cells as HIV's primary target.
Key point: HIV destroys helper T-lymphocytes (CD4+ cells), the coordinators of immunity.
Question 6 · easy · AIDS and Cancer
Which test is used to confirm HIV infection, based on detecting HIV-specific antigens or antibodies?
- A.ELISA (Enzyme-Linked Immunosorbent Assay)
- B.Widal test
- C.PCR test for tuberculosis
- D.Barium meal test
Show answer and explanation
Answer: A. ELISA (Enzyme-Linked Immunosorbent Assay)
HIV infection is diagnosed using the ELISA test, which detects HIV-specific antigens or antibodies in blood.
NCERT states that ELISA (Enzyme-Linked Immunosorbent Assay) is used for the diagnosis of HIV infection. The Widal test is used for diagnosing typhoid fever (caused by Salmonella typhi), and is unrelated to HIV. A PCR test for tuberculosis and a barium meal test are both real diagnostic tools but for entirely different conditions, not HIV/AIDS.
Common mistake: Confusing ELISA with the Widal test (typhoid) due to both being blood-based diagnostic tests.
Key point: ELISA is the standard NCERT-recognised test for diagnosing HIV infection.
Question 7 · easy · AIDS and Cancer
NACO, an organisation involved in creating public awareness about AIDS in India, stands for:
- A.National AIDS Control Organisation
- B.National Agency for Communicable Outbreaks
- C.National Association of Clinical Oncologists
- D.National AIDS Cure Organisation
Show answer and explanation
Answer: A. National AIDS Control Organisation
NACO stands for National AIDS Control Organisation, which spreads awareness about AIDS in India.
NCERT mentions the National AIDS Control Organisation (NACO) as a body involved in creating public awareness about AIDS through various media, and organisations worldwide are engaged in AIDS awareness programmes. NACO focuses on control, prevention, and awareness rather than claiming a 'cure', and it is unrelated to cancer or generic communicable-disease outbreak agencies.
Common mistake: Misremembering the acronym expansion or confusing it with a cancer-focused body.
Key point: NACO = National AIDS Control Organisation, India's AIDS awareness body.
Question 8 · easy · AIDS and Cancer
Which of the following correctly lists ONLY genuine transmission routes of HIV as recognised by NCERT?
- A.Sneezing, coughing, mosquito bites, sharing utensils
- B.Sexual contact, contaminated blood transfusion, sharing needles, hugging
- C.Shaking hands, sharing food, sharing needles, sexual contact
- D.Sexual contact, contaminated blood transfusion, sharing needles, mother-to-child via placenta
Show answer and explanation
Answer: D. Sexual contact, contaminated blood transfusion, sharing needles, mother-to-child via placenta
The four genuine HIV transmission routes are sexual contact, contaminated blood/blood products, sharing infected needles, and mother-to-child via the placenta.
NCERT specifies exactly these four transmission routes for HIV. Options A, B, and D each mix in at least one casual-contact myth (mosquito bites, hugging, shaking hands, or sharing food/utensils), none of which actually transmit HIV since the virus requires direct exchange of body fluids like blood, semen, or vaginal secretions, not surface or airborne contact.
Common mistake: Blending a genuine route list with one casual-contact myth.
Key point: Only four routes transmit HIV: sexual contact, contaminated blood, shared needles, and placental transfer.
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Questions about Human Health and Disease for NEET
How many NEET questions does NEET720 have on Human Health and Disease?＋
NEET720 has 1,260 reviewed practice questions on Human Health and Disease (Zoology): 206 easy, 892 medium and 162 hard. 8 of them are free on this page with full explanations; the rest are available in the app.
Is Human Health and Disease a Class 11 or Class 12 chapter for NEET?＋
Human Health and Disease is a Class 12 Zoology chapter in the NEET (UG) syllabus. Read the NCERT chapter first, then practise chapter-wise MCQs and previous-year questions.
How should I practise Human Health and Disease for NEET?＋
Attempt the questions below without looking at the options for more than a few seconds, mark your answer, then read the explanation even when you were right. Record every mistake and revisit it after a gap. On NEET720 this happens automatically: wrong answers go to your Mistake Book and are scheduled for spaced revision.
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Questions are original NEET720 compositions reviewed for correctness, syllabus fit and option quality. Counts update as the bank grows (1,260 active practice questions in this chapter today).