In which organ of the human body are the lymphocytes formed?

Correct answers: (b) Bone marrow or (e) None of the above / More than one of the above

Explanation

Lymphocytes (a type of white blood cell) all arise from stem cells in the bone marrow, the primary site of blood cell production (haematopoiesis).

They also multiply in the spleen, thymus and lymph nodes, so more than one listed organ forms lymphocytes: the Commission’s key is option (e).

Bone marrow alone, option (b), is also accepted here. The adult liver and the pancreas do not form lymphocytes.