The kidneys and sweat glands both work to prevent excesses of? either uric acid or urine in the body. either water or salt in the body. either carbon dioxide or oxygen in the body. either feces or ph levels in the body.

The first signs of cellular differentiation occur in the blastocyst. why is cellular differentiation important for the development of a fully formed human infant?

Flock x flock y flock z total pieces of food eaten (from previous page) 147 93 60 food percentage* % % % simulated number of birds in flock for 3rd generation** * divide each flock's total pieces of food by 300, the total number of pieces of food eaten. ** multiply the food percentage for each flock by the total number of birds (30).

In what for do plants utilize nitrogen? why do they need nitrogen?