Question

which primary lymphoid organ is the site of b cell maturation?

spleen

red bone marrow

tonsil

peyers patch

thymus

Explanation:

Primary lymphoid organs are where lymphocytes (B and T cells) mature. The red bone marrow is the site for B - cell maturation. The spleen is a secondary lymphoid organ for immune responses. Tonsils and Peyer's patches are also secondary lymphoid organs. The thymus is the site of T - cell maturation.

Answer:

Red bone marrow