In Active Immunity,but Not Passive Immunity,there Is

Multiple Choice

In active immunity,but not passive immunity,there is

A) acquisition and activation of antibodies.
B) proliferation of lymphocytes in bone marrow.
C) the transfer of antibodies from the mother across the placenta.
D) the requirement for direct exposure to a living or simulated pathogen.
E) the requirement of secretion of cytokines from T cells.