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:

the answer is b

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se

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