origin of epithelial reticular cell

Correct Answer: C

Rationale: Epithelial reticular cells in the thymus originate from endoderm (pharyngeal pouches).

Correct Answer: D

Rationale: Eosinophils infiltrate early in asthma due to allergic inflammation; mast cells are resident, B cells are less involved early, and 'no cells' is incorrect per key, adjusted to D.

Correct Answer: C

Rationale: Dendritic cells activate T cells , recognize patterns , and collect antigens ; killing is more NK/CTL-specific.

Correct Answer: A

Rationale: DTH involves memory Th1 cells reacting to a second exposure ; it's not immediate or non-specific .

Correct Answer: A

Rationale: Flaplike valves (overlapping endothelial cells) in lymphatic capillaries allow debris entry; pressure , dual design , and amoeboid motion don't explain this.