is spread from primary site, result in enlargement of lymph Node

Correct Answer: A

Rationale: Carcinoma causes lymph node enlargement via metastatic spread from a primary site.

Correct Answer: C

Rationale: T-lymphocytes enter lymph nodes via post-capillary venules ; figure context suggests lymph node, not tonsil , spleen , or efferent entry .

Correct Answer: D

Rationale: Macrophages are part of innate immunity; T cells , antibodies , and B cells are components of adaptive immunity.

Correct Answer: A

Rationale: NK cells produce cytokines and release cytotoxic chemicals ; they detect missing MHC I (C indirectly), not general traits , and activate macrophages secondarily.

Correct Answer: C

Rationale: B7 binds CD28 for T-cell co-stimulation ; not TCR-nucleus , adhesion , or upregulation .