Hormones are . See Concept 45.1 (Page) View Available Hint(s)for Part A signals that must interact with DNA in order to be effective chemical signals between cells, transported in blood or hemolymph always proteins are all under the control of the pituitary gland produced only in response to environmental stress

The correct answer is - chemical signals between cells, transported in blood or hemolymph

Explanation:

Hormones are chemicals that make communication between cells and transfer the signals to various target cells. These are transported through the blood and lumph in their respective circulation so signals can reach to the surface or within the target cells and perform specific functions.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation: