這個题目就是討論地球和生物的歷史。—般人對於地球歷史的長久是非常不容易瞭解的,因爲它的年代悠久,我们從地層比較的結果,僅能說出約略的年代。整個地球歷史,差不多有二十萬萬年,這種估計是根據一種放射性礦物分解的速度而定的。地球歷史的記載,是從地殼上各種不同年代的岩石和其所含的生物推断出來的。地質學家 This topic is to discuss the history of the earth and creatures. - The average person for the long history of the earth is very difficult to understand, because of its long history, we can only tell the approximate era from the stratigraphic comparison. The entire Earth’s history, almost 200 million years, is based on the rate at which a radioactive mineral decomposes. The history of the earth is inferred from the rock of the various ages in the crust and the creatures it contains. geologist