Question

Assertion : Spleen is a secondary lymphoid organ.
Reason : Secondary lymphoid organs produce T-lymphocytes.

• A. Both the assertion and reason are true but the reason is not the correct explanation of the assertion
• B. Both assertion and the reason are true and the reason is a correct explanation of the assertion
• C. Assertion is true but the reason is false
• D. Both the assertion and reason are false

Answer 1

The correct option is C Assertion is true but the reason is false

Lymphoid organs are specialized tissues that provide the microenvironment for the functional maturity (primary lymphoid organs) and activation (secondary lymphoid organs) of lymphocytes.

The spleen is a secondary lymphoid organ. It is a large bean-shaped organ consisting mainly of lymphocytes and phagocytic cells. It is compartmentalised into red and white pulps.

The red pulp is the site where old and defective erythrocytes are destroyed and removed from the blood while white pulp is the region where blood-borne antigens are trapped and a proper immune response is mounted. Hence the assertion statement is true.

Figure : Structure of spleen

The primary lymphoid organ provides a microenvironment for the development and maturation of lymphocytes. Examples are bone marrow and thymus. Hence the statement of reason is false.