Answer:
D
Explanation:
This is because the atmosphere is refreshable and makes breathing so conducive.
Prokaryotes are organisms whose cells lack a nucleus and other organelles. ... Prokaryotic cells are surrounded by a plasma membrane, but they have no internal membrane-bound organelles within their cytoplasm.
sorry if i'm wrong
i'm new to brainly
Answer: [B]: "proteins" .
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Acetylcholine..
hope it helps