Biologist know that some marine algae can create clouds by producing the gas dim

游客2024-01-10  5

问题 Biologist know that some marine algae can create clouds by producing the gas dimethyl sulphide (DMS), which reacts with oxygen in air above the sea to form solid particles. These particles provide a surface on which water vapor can condense to form clouds. Lovelock contends that this process is part of global climatic-control system. According to Lovelock, Earth acts like a super organism, with all its biological and physical systems cooperating to keep it healthy. He hypothesized that warmer conditions increase algal activity and DMS output, seeding more clouds, which cool the planet by blocking out the Sun. Then, as the climate cools, algal activity and DMS level decrease and the cycle continues. In response to biologists who question how organisms presumably working for their own selfish ends could have evolved to behave in a way that benefits not only the planet but the organisms as well, cooling benefits the algae, which remain at the ocean surface, because it allows the cooled upper layers of the ocean to sink, and then the circulating water carries nutrients upward from the depths below. Algae may also benefit from nitrogen raining down from clouds they have helped to form. [br] The passage mentions the possible benefit to algae of nitrogen falling down in the rain most likely in order to

选项 A、Provide support for Lovelock’s response to an objection mentioned in the passage.
B、Suggest that the climatic effects of DMS production have been underestimated.
C、Acknowledge that Lovelock’s hypothesis is based in part on speculation.
D、Demonstrate that DMS production alters the planet in more than one way.
E、Assert that algae are the sole beneficiaries of DMS production.

答案 A

解析 an objection指的是第七句中生物学家的观点,Lovelock在第七句中对其进行了回应,而最后一句话相当于一个额外的支持Lovelock“降温使藻类受益”观点的例子。
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