What is the most likely mechanism by which testosterone functions inside a cell? (sec. 11.2)
A) It acts as a signal receptor that activates tyrosine kinases.
B) It binds with a receptor protein that enters the nucleus and activates expression of specific genes.
C) It acts as a steroid signal receptor that activates ion channel proteins in the plasma membrane.
D) It coordinates a phosphorylation cascade that reduces spermatogenesis.
