Testosterone is the principal male sex hormone.
Answer: Ask your mom
Explanation: She was in school before you duh
<span>There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart</span>
True. it starts off simple then you move into details