Evesa
sos
-) some substances are absorbed into the capillaries by active uptake.
0 explain why active uptake is sometimes necessary

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:

it would be the percentage of food eaten by the flock

i remember doing this lab

the fossil record provides evidence of a common ancestor to many species.