In order to use the hardy-weinberg equation to calculate genetic variation in a
population, which of the following conditions must exist in the population?
o a. organisms must choose mates.
o
b. some alleles must give an advantage.
o
c. all organisms must reproduce.
o
d. immigration must occur.

Which statement describes a way in which the digestive and excretory systems work together? a. the nephrons absorb nutrients from food going to the large intestine. b. the excretory system balances blood gases in the small intestine. c. the intestinal villi filter blood and send wastes to the bladder. d. the excretory system balances the salts and water obtained from digested food