The process in which sperm and egg cells join is called

What field of science did harry hess study?

Spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

Amino acids contain the elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. of the 20 amino acids found in humans, 11 are called "nonessential" because they can be manufactured by the body when needed. which elements in these 11 amino acids are commonly obtained from the metabolism of sugar molecules?