Hormones can travel through the blood and not affect all tissues; only cells possessing sites for that particular hormone are affected, and these cells are called cells.

•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:

b) the inside picture would look at a very high temperature in a very low ph