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Antigens and Secondary Response

APBIO-1ZJF2I

An organism's immune system will rapidly respond to an antigen it has seen before. This secondary response activates a subset of lymphoid cells, leading to a rise in antibody titer.

Which of the following identifies the subpopulation responsible for the initiation of this response?

A

Memory B-cell.

B

Memory T-cell.

C

NK-cell.

D

Plasma cell.