The thymus's role in immunity is to:

Correct Answer: B

Rationale: The thymus matures T cells; blood is spleen, antibodies are B cells, storage is nodes.

Correct Answer: B

Rationale: The thoracic duct drains lymph from most of the body (below the diaphragm and left upper body) and empties into the left subclavian vein, not blood into the system.

Correct Answer: C

Rationale: Medullary sinuses are spaces between trabeculae and medullary cords in lymph nodes.

Correct Answer: A

Rationale: White pulp branches into penicillar arterioles in red pulp.

Correct Answer: D

Rationale: Thymulin enhances various T-cell functions.