Answer:
Active uptake (which I think you mean active transport) is important when the concentration gradient is against that of a certain substance, so it doesn't cross the membrane through diffusion or passive transport. It is sometimes necessary if a substance needs to move across a membrane but can't do so due to electrical charge or that there is a substance on the other side of the membrane preventing diffusion.
Explanation:
Answer:
During cellular respiration, <em>glucose</em> and oxygen are converted into carbon dioxide and water.
Explanation:
C) I and III only just got this question on usa test prep and therefore i'm right
