What is the function of the spleen's marginal zone?

Correct Answer: C

Rationale: The marginal zone traps antigens; lymph filtering is nodes, platelets are in red pulp, T cells are thymus.

Correct Answer: B

Rationale: The cortex is the outer region; medulla is inner, hilum is entry, sinus is channel.

Correct Answer: B

Rationale: Pharyngeal tonsils are in the nasopharynx; palatine , lingual , and Peyer's are elsewhere.

Correct Answer: A

Rationale: Antibodies trigger the classical complement pathway; pathogens trigger alternative, cytokines signal, histamines inflame.

Correct Answer: C

Rationale: T-helper cells activate others; killing is cytotoxic T, antibodies are B cells, phagocytosis is macrophages.