NCERT Class 12 Biology: Chapter – 8 Human Health and Diseases Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 17:

Tobacco consumption is known to stimulate secretion of adrenaline and nor-adrenaline. The component causing this could be:

a. Nicotine

b. Tannic acid

c. Curaimin

d. Catechin

Answer: (a)

Question 18:

Anti-venom against snake poison contains:

a. Antigens

b. Antigen-antibody complexes

c. Antibodies

d. Enzymes

Answer: (c)

Question 19:

Which of the following is not a lymphoid tissue?

a. Spleen

b. Tonsils

c. Appendix

d. Thymus

Answer: (c)

Question 20:

Which of the following glands is large sized at birth but reducies in size with aging?

a. Pineal

b. Pituitary

c. Thymus

d. Thyroid

Answer: (c)

Question 21:

Haemozoin is:

a. a precursor of haemoglobin

b. a toxin from Streptococcus

c. a toxin from Plasmodium species

d. a toxin from Haemophilus species

Answer: (c)

Question 22:

One of the following is not the causal organism for ringworm

a. Microsporum

b. Trichophyton

c. Epidermophyton

d. Macrosporum

Answer: (d)

Question 23:

A person with sickle cell anemia is

a. More prone to malaria

b. More prone to typhoid

c. Less prone to malaria

d. Less prone to typhoid

Answer: (c)

Very Short Answer Type Questions

Question 1:

Certain pathogens are tissue/organ specific. Justify the statement with suitable examples.


Pathogens are disease causing agents. Certain pathogens are tissue/organ specific as they only attack a certain tissue as seen in the case of:

A. Typhoid: Salmonella Typha only infects the small intestine.

B. Intestinal Endoparasities only infects large intestine, causing Amoebic dysentery.

Question 2:

The immune system of a person is suppressed. In the ELISA test, he was found positive to a pathogen.

a. Name the disease the patient is suffering from.

b. What is the causative organism?

c. Which cells of body are affected by the pathogen?


a. The patient is suffering from Acquired Immuno Deficiency syndrome (AIDS) . In this disease body՚s immune system is compromised by the HIV.

b. The causative organism is the Human Immuno Deficiency Virus (HIV) . This virus interferes with the body՚s ability to fight a disease hence making body more susceptible to various diseases.

C. T4 lymphocytes or helper cells are affected in this disease.

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