Which organ stores lymphocytes for immune responses?

Correct Answer: B

Rationale: The spleen stores lymphocytes; thymus matures T cells, appendix and tonsils are smaller.

Correct Answer: B

Rationale: The spleen filters blood for pathogens; T cells mature in thymus, lymph is from nodes, antibodies aren't stored.

Correct Answer: C

Rationale: MHC I presents to cytotoxic T cells; MHC II is for T-helper, B cells use BCR, complement is separate.

Correct Answer: B

Rationale: Thymosin aids T cell maturation; insulin is pancreas, cortisol and adrenaline are adrenal.

Correct Answer: C

Rationale: Natural passive is from breast milk; active (A, B) involves own response, artificial passive is injected.