Are enzymes needed for metabolism?

Which of the following sex and generation combinations directly produces the pollen tube of angiosperms? a) male gametophyteb) female gametophytec) male sporophyted) female sporophyte

What is the significance of the protein-lined pits? a. protein attracts other proteins needed for atp synthesis within the cell. b. protein-lined pits are able to transport one molecule at a time down the concentration gradient within the cell. c. the polarity of proteins allows other polar molecules to attach and be transported in the cell by transport channels. d. receptors within the pits allow ligands to fuse and be transported into the cell by endocytosis.

Which of these would most likely be a stimulus that would cause the body to initiate feedback mechanisms a.) normal body temperature in an arctic environment b.) normal boy temperature in a tropical environment c.)light physical activity d.)low blood sugar