Answer:
Molecules which move against the concentration gradient across the cell membrane employ the mechanism of active transportation.
Explanation:
Normally, permitted molecules moves across the cell membrane of the cell by the process of diffusion and osmosis. This is used when molecules move from hypertonic region to hypotonic region (if ions) and hypotonic to hypertonic (if water). This is a passive transportation which do not require the expense of energy from the cell.
In contrast, when molecules move in or out of the cell against their concentration gradient, that is ions moving from hypotonic region to hypertonic region, they implore the expense of energy in form of adenosine triphosphate (ATP), and the involvement of the membrane carrier proteins. This is called active transport.
Answer:
with each heartbeat,the heart pumps blood throughout our bodies,carrying oxygen to every cell,after delivering oxygen the blood returns to the heart the heart then sends the blood to the lungs to pick up more oxygen.
I believe animals that possess homologous structures probably evolved from the same ancestor. Homologous structures are similar because of common ancestry. A homologous structure is an example of an organ or bone that appears in different animals, underlining anatomical commonalities demonstrating descent from a common ancestor.
The answer would be B i believe<span>(a protease) begins the chemical digestion of protein</span>
