Which of these valves prevents a backflow of blood into the left atrium?
aortic valve
tricuspid valve
mitral valve

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.

At which point is crust neither created nor destroyed? island chain mid-ocean ridge divergent boundary transform boundary

The wind is to parities grasses because it them