Many signaling molecules exist in very miniscule

Many signaling molecules exist in very miniscule concentrations within the body, yet trigger very large responses within the cell. How does this occur?

A. Signal recognition induces the release of ATP which gives the cell more energy to produce a large response.

B. Signal recognition induces crosstalk to other signal receptor proteins, all of which then respond to the initial signal.

C. Signal recognition induces mitosis by the cell, and all of the daughter cells respond to the initial signal.

D. Signal recognition induces the release of secondary messengers which amplifies the signal within the cell.