Defense by B cells is known as

Correct Answer: D

Rationale: B cell defense is humoral or antibody-mediated immunity.

Correct Answer: B

Rationale: Classical complement pathway is adaptive, triggered by antibodies; antibodies are adaptive, lectins are host-derived, and CRP is innate.

Correct Answer: D

Rationale: Monocytes and M-tropic are true; neurons aren't infected , and macrophages persist . Answer is D (A and B), noted in rationale.

Correct Answer: C

Rationale: Fab binds antigen; Fc activates complement , binds cells , and CH determines class , not placental .