Scientists have observed that the size of a population influences the genetic health of a species. what is considered to be a healthy population size?
a. 50
b. 500
c. 1,000
d. 100

cells spend most of their time in interphase

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.

d. organisms have cells with different shapes and functions.