The cell membrane forms a protective barrier between the external and internal environments. it is referred to as because it allows some substances to cross more easily than others and blocks other substances from crossing into the cell.

selectively permeable

Explanation:

hi! do you know the answer for this flvs question?

what do anaerobic organisms have in common with photosynthetic organisms?

they both appeared on earth at about the same time.

they both can only exist as single-celled organisms.

they both need an energy source in order to survive.

they both produce carbon dioxide as a waste product.

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