Part B

　　Directions：

　　The following paragraph are given in a wrong order. For Questions 41-45， you are required to reorganize these paragraphs int0 a coherent text by choosing from the list A-G to filling them int0 the numbered boxes. Paragraphs E and G have been correctly placed. Mark your answers on ANSWER SHEET 1. (10 points)

　　Long before Man lived on the Earth, there were fishes, reptiles,birds, insects, and some mammals. Although some oftheseanimals were ancestors of kinds living today, others are now extinct, that is,they have no descendants alive now. 41. Very occasionally the rocks showimpression of skin, so that, apart from color, we can build up a reasonablyaccurate picture of an animal that died millions of years ago. The kind of rockin which the remains are found tells us much about the nature of the originalland, often of the plants that grew on it, and even of its climate.

　　42. . Nearly all of the fossils that we know were preserved in rocksformed by water action, and most of these are of animals that lived in or nearwater. Thus it follows that there must be many kinds of mammals, birds, andinsects, of which we know nothing.

　　43. . There were also crab-like creatures, whose bodies were coveredwith a horny substance. The body segments each had two pairs of legs, one pairfor walking on the sandy bottom, the other for swimming. The head was a kind ofshield with a pair of compound eyes, often with thousands of lenses. They wereusually an inch or two long but some were 2 feet.

　　44. . Of these, the ammonites are very interesting and important.They have a shell composed of many chambers, each representing a temporary homeof the animal. As the young grew larger it grew a new chamber and sealed offthe previous one. Thousands of these can be seen in the rocks on the DorsetCoast.

　　45. .About 75 million years ago the Age of Reptiles was over andmost of the groups died out. The mammals quickly developed, and we can tracethe evolution of many familiar animals such as the elephant and horse. Many ofthe later mammals, though now extinct, were known to primitive man and werefeatured by him in cave paintings and on bone carvings.

　　[A] The shell gush have a long history in the rock and many differentkinds are known.

　　[B] Nevertheless, we know a great deal about many of them because theirbones and shells have been preserved in the rocks as fossils. From them we cantell their size and shape, how they walked, the kind of food they ate.

　　[C] The first animals with true backbones were the fishes, first knownin the rocks of 375 million years ago. About 300 million years ago theamphibians, the animals able to live both on land and in water, appeared. Theywere giant, sometimes 8 feet long, and many of them lived in the swampy poolsin which our coal seam, or layer, or formed. The amphibians gave rise to thereptiles and for nearly 150 million years these were the principal forms oflife on land, in the sea, and in the air.

　　[D] The best index fossils tend to be marine creatures. These animalsevolved rapidly and spread over large areas of the world.

　　[E] The earliest animals whose remains have been found were all verysimple kinds and lived in the sea. Later forms are more complex, and amongthese are the sea�瞝ilies, relations of the star�瞗ishes, which had long armsand were attached by a long stalk to the sea bed, or to rocks.

　　[F] When an animal dies the body, its bones, or shell, may often becarried away by streams into lakes or the sea and there get covered up by mud.If the animal lived in the sea its body would probably sink and be covered withmud. More and more mud would fall upon it until the bones or shell becomeembedded and preserved.

　　[G] Many factors can influence how fossils are preserved in rocks.Remains of an organism may be replaced by minerals, dissolved by an acidicsolution to leave only their impression, or simply reduced to a more stableform.

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