【正文】 ods of dryness. █These adaptations served their descendant well as they invaded land.　　　　　The terrestrial world is green now, but it did not start out that way. When plants first made the transition ashore more than 400 million years ago, the land was barren and desolate, inhospitable to life. From a plant’s evolutionary view point, however, it was also a land of opportunity, free of petitors and predators and full of carbon dioxide and sunlight (the raw materials for photosynthesis, which are present in far higher concentrations in air than in water).So once natural selection had shaped the adaptations that helped plants overe the obstacles to terrestrial living, plants prospered and diversified.　　When plants pioneered the land, they faced a range of challenges posed by terrestrial environments. On land, the supportive buoyancy of water is missing, the plant is no longer bathed in a nutrient solution, and air tends to dry things out. These conditions favored the evolution of the structures that support the body, vessels that transport water and nutrients to all parts of plant, and structures that conserve water. The resulting adaptations to dry land include some structural features that arose early in plant evolution。 now these features are mon to virtually all land plant. They include roots or root like structures, a waxy cuticle that covers the surfaces of leaves and stems and limits the evaporation of water, and pores called stomata in leaves and stems that allow gas exchange but close when water is scarce, thus reducing water loss. Other adaptations occurred later in the transition to terrestrial life and now wide spread but not universal among plants. These include conducting vessels that transport water and minerals upward from the roots and that move the photosynthetic products from the leaves to the rest of the plant body and the stiffening substance lignin, which support the plant body, helping it expose maximum surface area to sunlight.　These adaptations allowed an increasing diversity of plant forms to exploit dry land. Life on land, however, also required new methods of transporting sperm to eggs. Unlike aquatic and marine forms, land plants cannot always rely on water currents to carrytheir sex cells and disperse their fertilized eggs. So the most successful groups of land plants are those that evolved methods of fertilized sex cell dispersal that are independent of water and structures that protest developing embryos from drying out. Protected embryos and waterless dispersal of sex cells were achieved with the origin of seed plans and the key evolutionary innovations that they introduced: pollen, seeds, and later, flowers and fruits. 　　　　　　Paragraph 1: 　　 word “presumably” in the passage is closest in 　　　meaning to 　　A. originally 　B. supposedly 　　　C. obviously 　　　D. usually 　　2. According to paragraph 1, all of the following are true of ancestral plants EXCEPT　　　A. They had cellulosebased cell walls. 　B. They were closely related to green algae 　C. They were able to store nutrients 　D. They had a sophisticated multicellular structure.　　Paragraph 2: 　　　 phrase “subjected to” in the passage is closest in　A. restricted by　B. distant from　　　C. exposed to 　　　D. bined with 　　Paragraph 3: 　　 can be inferred from paragraph 3 about ancient green algae?　　A. They lived in a generally wet environment that was sometimes day 　　　B. They adapted better to changes in water temperature than did to other changes in the environment.　　　　C. They inhabited areas that were close to the ocean. 　　D. They had lived primarily on land 　　Paragraph 4: 　　5. The word “desolate” in the passage is closest in meaning to 　　A. dusty 　B. hardened 　　　C. deserted 　D. dried out 　　　 of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. 　　A. Terrestrial plants had the advantages of not having rivals and having easy access to photosynthetic material 　　　B. The abundance of photosynthetic material made life on land easier for pioneering plants 　　　C. Once plants had eliminated their petitors and their predators, their evolutionary process proceeded smoothly. 　D. Plant evolution eliminated petitors and made the process of photosynthesis more efficient. 　　7. According to paragraph 4, which of the following is true about the terrestrial world at the time it was colonized by plants? 　　A. it was exposed to high levels of solar radiation 　　B. it contained a limited supply of carbon dioxide 　C. it had developed 400million years earlier 　D. it lacked the presence of any organisms 　　　　　Paragraph 5: 　　8. the word “posed” in the passage is closest in meaning to 　A. shared 　　B. presented 　　C. strengthened 　　　D. concealed 　　　　　9. According to paragraph 5, all of the following are problems that early terrestrial plants had to overe Except 　　A. a tendency to bee dry 　　　B. the inability to limit surface sunlight 　C. the absence of a structure to support the body of the plant 　D. the inability to transport water and minerals through the plant 　　　10. What purpose does paragraph 5 serve in the larger discussion of the origins of terrestrial plants? 　A. To emphasize how long it took for ancestral plants to adjust to life on land 　B. To disprove the argument that land plants adapted easily to their new terrestrial environment 　C. To explain how plant colonization changed the physical environment of the terrestrial world 　　　D. To describe how ancestral plants solved the problems they confirmed in colonizing 　　　Paragraph 6: 　　11. According to Paragraph 6, The adaptation made by terrestrial plants had which of the following effect?’ 　　　A. Plants developed reproductive strategies usable in both land and water environment 　B. the plant diversity achieved in