Valves ensure blood flows toward your heart. Vein valves work to bring the blood that flowed down via arteries back up to your heart.
Four chambered heart keeps oxygenated and deoxygenated blood separate and has double circulation while three chambered heart has a single circulation. Two chambered heart only has single atrium and single ventricle
It flickers or appears to flicker because of the long distance it hast to travel
<u><em>Chromosomes</em></u> asserts that our genes set the boundaries within which we can operate
Unwanted pregnancy or std ( sexually transmitted disease <span />
