Immune System
Numerous antibodies can be prepared, against one antigen, each binds to unique epitopes. How is this antibody diversity generated?

By the combination of different heavy and light chains that form the antigen binding site
Both (a) and (b)
By rearrangements of the DNA encoding the variable regions of the heavy and light chains
Antibody proteins can physically change their shape to bind different epitopes

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Immune System
Polymorphonuclear leukocytes (or PMNs)

can be attracted to the site of an infection following activation of complement
are a type of phagocyte that can engulf and kill bacteria
All of these
are derived from bone marrow stem cells

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