what often serves as the second messenger when a hydrophilic amino-acid based hormone binds its receptor?

-Cyclic adenosine monophosphate (cAMP)

-G-protein is the receptor

Explanation:

•there must be variation for the particular trait within a population.

•the variation must be inheritable (that is, it must be capable of being passed on from the parents to their offspring).

•individuals with one version of the trait must produce more offspring than those with a different version of the trait.good

explanation:

"a.) well–developed vascular system."