Human health and disease
Read the following passage carefully and answer the given questions.
Diseases like typhoid, cholera, pneumonia, fungal infections of skin, malaria and many others are a major cause of distress to human beings. Our immune system plays the major role in preventing these diseases when we are exposed to disease-causing agents. If the pathogens succeed in gaining entry to our body, specific antibodies and cells serve to kill these pathogens. AIDS and cancer kill a large number of individuals worldwide. AIDS is fatal but can be prevented if certain precautions are taken. Many cancers are curable if detected early and appropriate therapeutic measures are taken. Drug and alcohol abuse among youth and adolescents is becoming another cause of concern.
Bone marrow and thymus provide micro-environments for the development and maturation of:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → T-lymphocytes
The lymphoid organs are the organs where lymphocytes originate, mature and multiply. The primary lymphoid organs are the bone marrow and the thymus. Immature lymphocytes change here into antigen-sensitive lymphocytes. The bone marrow is also the main site where all the blood cells are made. After maturing, the lymphocytes move to the secondary lymphoid organs, such as the spleen and lymph nodes.
(1) Mast cells — Incorrect. They release histamine in allergy. They are not made to mature in the thymus.
(2) Alpha cells — Incorrect. They are cells of the pancreas that make glucagon, and have nothing to do with immunity.
(3) Gamma cells — Incorrect. There is no cell type of this name in the immune system.
(4) T-lymphocytes — Correct. Both the bone marrow and the thymus provide micro-environments for the development and maturation of T-lymphocytes.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Immune System in the Body – …
