The lymphatic system lacks which feature found in the circulatory system?

Correct Answer: A

Rationale: It lacks a central pump like the heart; it has vessels , capillaries , and valves .

Correct Answer: C

Rationale: Trunks drain lymph into ducts; filtering is nodes, collecting is capillaries, producing is marrow.

Correct Answer: B

Rationale: The thymus matures T cells ; B cells mature in bone marrow, macrophages and neutrophils are innate.

Correct Answer: C

Rationale: Neutrophils are rapid innate responders; T and B cells are adaptive, dendritic cells present antigens.

Correct Answer: A

Rationale: Cytotoxic T cells kill infected cells; B cells make antibodies, macrophages and neutrophils phagocytose.