Compare the thickness of the wall of the superior and inferior vena cava and the aorta. which thicker and why

The wall of the aorta is thicker than that of the inferior venacava; this is because the aorta is the artery that carries blood from the heart from the left ventricle to the whole body (except the lungs), while the superior and inferior venacava are the veins that carry blood from the body to the right atrium. hope this helps ! :)))

Explanation:

the answer is b.) hydrogen bonds between bases.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.