A tissue graft between two people who are not genetically identical is termed a:

Correct Answer: D

Rationale: Allograft is between non-identical humans; isograft is identical, xenograft is cross-species.

Correct Answer: D

Rationale: All (A, B, C) are true for passive immunity; thus, D is correct.

Correct Answer: D

Rationale: Antigens bind to B cell receptors to activate them, unlike complement, antibodies, or interferon (which modulate responses).

Correct Answer: D

Rationale: Clonal selection involves T and B cells proliferating after antigen encounter, not innate cells like basophils.

Correct Answer: A

Rationale: HIV targets CD4+ T cells , crippling immunity; CD8+ and macrophages are less primary targets.