Carbon, hydrogen, nitrogen and sulphur are elements found in living cells. which is the least common?
a. carbon
b. hydrogen
c. nitrogen
d. sulphur

Use this diagram of an animal cell to answer the question. where does the first stage of cellular respiration occur? w x y z

In this case, the statement that people who exercise for an hour may have lower cholesterol levels is .

Rachel ate a piece of fruit and happened to drop the seeds in her backyard. after a few weeks, she saw a small plant with flowers growing in the backyard. which group does this plant belong to? a. angiosperms b. gymnosperms c. pteridophytes d. bryophytes e. chytrids