Refer to the Figure Showing Chemical Signaling Systems

Multiple Choice

Refer to the figure showing chemical signaling systems. If the substance labeled 1 is insulin, then

A) it is an amine hormone, and 2 may be a hypothalamus cell.
B) it is a protein hormone, and 3 may be a fat cell.
C) it is a steroid, and 3 may be a muscle cell.
D) the cells labeled 2 and 3 are both target cells.
E) it is acting as a paracrine on the cell labeled 3.