Thymosins are secreted by the _________ and aid in ___________.

Correct Answer: D

Rationale: Thymosins from the thymus aid T cell maturation.

Correct Answer: C

Rationale: Titer measures antibody concentration in plasma.

Correct Answer: A

Rationale: Naïve B cells express IgM and IgD ; IgG (B, D) and IgA are post-activation.

Correct Answer: C

Rationale: IgE mediates allergies via mast cells; IgA , IgD , IgG , and IgM have other roles.

Correct Answer: C

Rationale: Anti-Rh sera to mother (RhoGAM) prevents sensitization; erythrocytes worsen it, child immunization is irrelevant.