What does the phrase “extreme environments” suggest as it is used in the sentence below?

Organisms that use chemosynthesis live in extreme environments, where the toxic chemicals needed for oxidation are found.

(A) that the organisms live in places where toxins are scarce

(B) that the organisms live off the high heat of the sun

(C) that the organisms live far away and by themselves

(D) that the organisms live in harsh conditions

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