结构推理 Directions: In this part there is a short passage with five questions or incomplete statements. Read the passage carefully. Then answer the questions or complete the statements in the fewest possible words (not exceeding 10 words). Living organisms are indeed complicated and highly organized, but it is now clear that no new scientific laws are required to explain their complexity and organization. Just as living organisms like ourselves are composed of many different kinds of organs, each with its own specific part to play in ensuring the proper functioning of the whole organism, at a deeper level the tissues of all living things are composed of many kinds of complex molecules. Each of those chemical compounds, like each organ in the body, seems to have a specific role to play in the healthy functioning of the whole, and some of those molecules may contain tens of thousands, even hundreds of thousands, of atoms. The essence of life—ultimately due to the behavior of those complex molecules working together—is the ability of living things to extract energy from their environment and to use that energy both to build up their own complex structures and to copy themselves—to reproduce. For all life on the surface of the earth, the ultimate source of that energy is sunlight, trapped in plants by photosynthesis. Cells function as chemical engines, storing and transmitting energy in chemical form, as energetic molecules which can give it up when and where required; animals tap that storehouse of energy by eating plants, or by eating other animals which have themselves eat plants. (Very recently, organisms have been found in the deep ocean, far from any source of sunlight; they derive their energy from underwater volcanic hot spots and lead their lives quite cut off from the ecological web above them. Like us, however, they depend on an outside source of energy.) 1.What is the main purpose of the passage? 2.According to the passage, what is not essential to any living organisms? 3.What compose of the living organism? 4.What does the word "it" (Line 6, Para. 2) refer to? 5.What is the essence of life?