What is the role of the kidney? ? apex

they create hormones that help produce red blood cells, promote bone health, and regulate blood pressure

and

They help the body pass waste as urine. They also help filter blood before sending it back to the heart.

Explanation:

The three observations

number of adults in a population tends to remain the same over time even though, for most organisms, parents tend to produce multiple and sometimes many offspring.

variation exists among members of populations.

and finally, individuals having variation that is advantageous for survival and reproduction increase in relative frequency over time.