单选题 Surprisingly to those who view the ocean floor as a uniformly ______ waste, each vent in the floor, where seawater is heated by the earth's inte-rior magma, has been found to be an island-like ______ with its own distinctive fauna.

(A) teeming...habitat
(B) lifeless...enclave
(C) barren...oasis
(D) sunken...grotto
(E) hazardous...environment

【正确答案】 C

【答案解析】Rather than being barren or devoid of life, the vent regions are like oases that support life. Choice A is incorrect. A waste by definition is not teeming but barren.
Choice B is incorrect. The vent region would not be described as an enclave (tract enclosed within a foreign territory).
Choice D is incorrect. A grotto would not be described as island-like. Choice E is incorrect. Nothing in the sentence justifies the use of the term hazardous.