Choose all that apply. The heart ___.

pumps blood to the body.

has four chambers.

is part of the cardiovascular system.

is made of skeletal muscle.

works with the respiratory system.

(you can pick more then one!)

What is genetic variation? -(a) each individual in a population has slightly different genes. -(b) some individuals in a population have more genes than others. -(c) each population of a species has slightly different genes. -(d)some populations of a species have more genes than others.