Although all modern breeds of dogs are members of the same species, they exhibit a wide range of physical characteristics. Which of these statements provides the best evidence that this range of characteristics is the result of artificial selection?

a

explanation:

not too sure but maybe in the hot springs.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.