Question

One of the following is a secondary lymphoid organ:

• A. Bone marrow
• B. Thymus gland
• C. Bursa of Fabricius
• D. Spleen

Hint:

Secondary lymphoid organs include the spleen and lymph nodes, where immune cells are activated.

Answer 1

The Correct Option is D

Bone marrow is the primary lymphoid organ, where blood cells and immune cells are produced.
Thymus gland is also a primary lymphoid organ.
Bursa of Fabricius is found in birds, a primary lymphoid organ, not secondary.
Spleen is a secondary lymphoid organ responsible for filtering blood and immune cell activation.
Final Answer:
Spleen