21. The Immune System

_________ is another name for antibodies.

An antibody’s variable region:

1.   Varies in amino acid sequence to allow different antibodies to bind different antigens.

2.   Is located in the hinge and stem regions of an antibody.

3.   Is a portion of the light chain of an antibody.

4.   Is a portion of the heavy chain of an antibody.

Genetic recombination frequently occurs in the body’s B cell population. Why is this advantageous to the immune system?