[简答题]简述光在海洋中的分布规律及其主要生态作用。

56. Unfortunately the changes of any animal become a fossil are not very great, and 57. the chances of a fossil then being discovered many thousand of years later are even less. 58. It is not surprising that all the millions of animals that have lived in the past. 59. we actually have fossils of only very few. 60. There are several ways into which animals and plants may’ become fossilized. 61. First, it is essential that the remains are buried, as though dead animals and plants are quickly destroyed 62. if they remain exposed the air. Plants rot, while insects and hyenas cat the flesh and bones of animals. 63. Finally, the few remaining bones soon disintegrate the hot sun and pouring rain. If buried in suitable conditions, however, animal and plant remains will be preserved. 64. The same chemicals change sand and silt into hard rock will also enter th