What is the function of our ecosystem? Environmental Issues: Select the best answer from the choices provided.
A.
It shields the Earth from the sun's UV rays.
B.
It breaks down and absorbs pollution.
C.
It increases oxygen in the atmosphere.
D.
It increases temperature in the summer and decreases temperature in the winter.

Humans are believed to have evolved in coastal regions in east africa. the region had an abundant supply of fish for early humanoids to eat. when scientists analyze the fads gene they see an interesting pattern. people whose families have lived in this area of east africa for generation show a high level of diversity in alleles for the fads gene. conversely, people whose families had migrated inland a moderate distance from sources of fish showed a much lower diversity for fads gene alleles. additionally, the fads alleles found in people whose family has lived inland for generation are almost all gene alleles which produce fads proteins with a high level of function and activity. how do anthropologists explain this?

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?

Stephen is a student who wants to test his knowledge of medical terminology. which option could he use?