Class 12 Biology MCQ – Human Health and Disease

1. Which cells in the human body are primarily responsible for immune response?

a) Neurons
b) Red Blood Cells
c) White Blood Cells
d) Muscle Cells

Answer:

c) White Blood Cells

Explanation:

White Blood Cells, or leukocytes, play a vital role in defending the body against pathogens and foreign invaders.

2. Which disease is caused by the human immunodeficiency virus (HIV)?

a) Malaria
b) Tuberculosis
c) AIDS
d) Measles

Answer:

c) AIDS

Explanation:

Acquired Immunodeficiency Syndrome (AIDS) is caused by the human immunodeficiency virus (HIV).

3. Which vector is responsible for transmitting malaria?

a) Housefly
b) Sandfly
c) Anopheles mosquito
d) Tsetse fly

Answer:

c) Anopheles mosquito

Explanation:

Malaria is transmitted through the bite of an infected Anopheles mosquito.

4. Which disease is characterized by the inflammation of the liver?

a) Tuberculosis
b) Hepatitis
c) Typhoid
d) Pneumonia

Answer:

b) Hepatitis

Explanation:

Hepatitis refers to the inflammation of the liver, and it can be caused by various factors including viruses.

5. Which organism causes athlete's foot?

a) Bacteria
b) Virus
c) Fungus
d) Protozoa

Answer:

c) Fungus

Explanation:

Athlete's foot is a fungal infection affecting the skin, primarily between the toes.

6. The body's first line of defense against pathogens includes:

a) Antibodies
b) Skin and mucous membranes
c) White blood cells
d) Antigens

Answer:

b) Skin and mucous membranes

Explanation:

The skin and mucous membranes act as physical barriers, preventing pathogens from entering the body.

7. Which is NOT a non-communicable disease?

a) Diabetes
b) Cancer
c) Asthma
d) Influenza

Answer:

d) Influenza

Explanation:

Influenza is a communicable disease caused by the influenza virus, while the others are non-communicable.

8. What is the primary function of antibodies?

a) Reproduction
b) Digestion
c) Neutralizing pathogens
d) Providing energy

Answer:

c) Neutralizing pathogens

Explanation:

Antibodies are proteins produced by the immune system to neutralize or destroy pathogens like viruses and bacteria.

9. Which disease is caused by a deficiency of Vitamin C?

a) Rickets
b) Scurvy
c) Beriberi
d) Pellagra

Answer:

b) Scurvy

Explanation:

Scurvy results from a deficiency of Vitamin C and is characterized by bleeding gums and joint pain.

10. Vaccination works on the principle of:

a) Antibiotic resistance
b) Passive immunity
c) Active immunity
d) Natural selection

Answer:

c) Active immunity

Explanation:

Vaccination introduces a weakened or inactivated form of a pathogen to stimulate the body's immune response, leading to active immunity.

11. Which of the following diseases is caused by a protozoan?

a) Common cold
b) Malaria
c) Tuberculosis
d) Typhoid

Answer:

b) Malaria

Explanation:

Malaria is caused by the protozoan parasite Plasmodium.

12. The term 'epidemic' refers to:

a) A disease that affects a large number of people in a community at the same time
b) A minor and common illness
c) A genetic condition
d) A chronic condition

Answer:

a) A disease that affects a large number of people in a community at the same time

Explanation:

An epidemic occurs when a disease affects a larger than expected number of individuals within a community or region at the same time.

13. Ringworm is caused by:

a) Bacteria
b) Virus
c) Worms
d) Fungi

Answer:

d) Fungi

Explanation:

Despite its name, ringworm is not caused by worms but by a fungal infection.

14. Which of the following diseases is considered a lifestyle disease?

a) Malaria
b) Cholera
c) Diabetes
d) Typhoid

Answer:

c) Diabetes

Explanation:

Diabetes, often related to lifestyle factors such as diet and physical activity, is considered a lifestyle disease.

15. Which type of immunity is conferred by mother's milk to her newborn?

a) Active Immunity
b) Passive Immunity
c) Innate Immunity
d) Acquired Immunity

Answer:

b) Passive Immunity

Explanation:

Mother's milk contains antibodies that provide passive immunity to the newborn against certain infections.

16. The presence of which organism in water indicates its contamination?

a) Algae
b) Escherichia coli
c) Salmonella
d) Vibrio cholerae

Answer:

b) Escherichia coli

Explanation:

The presence of E. coli in water often indicates fecal contamination and the potential presence of pathogens.

17. The most common type of cancer among women worldwide is:

a) Lung cancer
b) Breast cancer
c) Ovarian cancer
d) Colorectal cancer

Answer:

b) Breast cancer

Explanation:

Breast cancer is the most frequently diagnosed cancer among women globally.

18. Allergies are a result of the body's immune system reacting to:

a) Toxins
b) Allergens
c) Pathogens
d) Vitamins

Answer:

b) Allergens

Explanation:

Allergies are hypersensitive immune responses to substances called allergens which are typically harmless to most people.

19. Which organ gets affected in dengue fever?

a) Liver
b) Lungs
c) Skin
d) Platelets in blood

Answer:

d) Platelets in blood

Explanation:

Dengue fever affects platelet count, leading to thrombocytopenia or reduced platelet levels.

20. Tuberculosis is caused by:

a) Virus
b) Bacterium
c) Protozoan
d) Fungus

Answer:

b) Bacterium

Explanation:

Tuberculosis is caused by the bacterium Mycobacterium tuberculosis.

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