If the Earth's magnetic pole reversal caused by biological extinction, it is not difficult to explain why from time to time, so that the periodic destruction of the Earth civilization.

假如地球磁极逆转而造成生物大量灭尽，那就不难表明为何每隔一段时间，使地球文明周期性的毁灭。

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The extinction of myriad biological species aroused deep concern which led people to an understanding of the special importance of protecting rare animals and plants on the brink of extinction.

无数生物物种的灭绝引起了人们的深切关注，使人们认识到保护濒临灭绝的珍稀动植物的特殊重要性。

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Before the existence of human, the process of biological evolution is accompanied with species extinction.

人类出现之前，生物进化的过程中就伴随着物种的灭绝。

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Jane Gilmour from the Guernsey Biological Records Centre says changes in land use and climate are pushing Guernsey bumblebees close to extinction.

BBC: Guernsey bumblebee species under threat says expert