Which best explains how photosynthesis is to humans?

it reduces the amount of harmful rays released by the sun.
it increases the levels of carbon dioxide in the air.
it provides oxygen for humans to breathe.
it produces proteins, which humans can eat.

Which term describes the number of waves that pass a given point in a given time? crest frequency trough wavelength

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.

Temperatures in ponds and lakes vary by season. select the best answer from the choices provided t f