Why is clonal selection and expansion so important to the immune response? A) It facilitates the secretion of cytokines. B) It enables certain cells to kill target cells. C) It is critical to the increase in the numbers of specific cells. D) It facilitates interleukin secretion which in turn directs cell differentiation.

C) It is critical to the increase in the numbers of specific cells

Explanation:

Clonal selection and expansion is the mechanism by which the immune system selects specific cells capable of both recognizing antigens and increasing the number of these useful cells that fight against pathogenic microorganisms and viruses. During this mechanism, B cells (also known as B lymphocytes) that have specific transmembrane receptors capable of recognizing specific antigens, are multiplied. The process of expansion involves the hypermutation of the clones in order to modify the shape and structure of these receptors, which increases the affinity of the clones for specific antigens.