【文章內(nèi)容簡介】 uel, and fodder and provides something like oneseventh of the food energy available in the area. The sweet potato, growing in sandy soil and providing more food energy per unit of land than other crops, became the main food of the poor in much of the South China rice area.Productivity in agriculture was also improved by capital investments, first of all in irrigation. From 1400 to 1900 the total of irrigated land seems to have increased almost three times. There was also a gain in farm tools, draft animals, and fertilizer, to say nothing of the population growth itself, which increased half again as fast as cultivated land area and so increased the ratio of human hands available per unit of land. Thus the rising population was fed by a more intensive agriculture, applying more labor and fertilizer to the land.11. Which of the following is NOT mentioned in paragraphs 5 and 6 as one of the strategies the Chinese applied in agriculture?A. The growing of two crops on the same field during the same yearB. The improvement of systems to supply crops with waterC. The application of increasing amounts of fertilizer to the landD. The reduction in the amount of human labor per unit of land12. What purpose does paragraph 5 serve in the larger discussion about China’s population growth?A. It provides evidence of China’s emerging foreign trade relations.B. It illustrates how the Chinese increased their food supply.C. It provides evidence of why population growth was most noticeable in the south.D. It shows how foreign crops gradually gained greater acceptance in China. at the four squares [■] that indicate where the following sentence could be added to the passage.Other developments addressed the problems of dry and sandy areas unsuitable for growing China’s native crops.Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.This technological advance took many forms: one was the continual introduction from the south of earlierripening varieties of rice, which made possible doublecropping (the production oftwo harvests per year from one field). ■ New crops such as corn (maize) and sweet potatoes as well as peanuts and tobacco were introduced from the Americas. ■Corn, for instance, can be grown on the dry soil and marginal hill land of North China, where it is used for food, fuel, and fodder and provides something like oneseventh of the food energy available in the area. ■The sweet potato, growing in sandy soil and providing more food energy per unit of land than other crops, became the main food of the poor in much of the South China rice area. ■14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.Drag your answer choices to the spaces where they belong. To remove an answer choice, click on it.To review the passage, click VIEW TEXT.Over the centuries, China has experienced an extraordinary increase in its population.Answer ChoicesA. Understanding the exceptional increase in population in China requires giving up monly held assumptions relative to the phenomenon of population growth.B. The economist Dwight Perkins applied a particular statistical method to determine the increase in China’s population.C. The sudden population growth in China started in its northern and southern provinces, and it spread rapidly to the central and western areas of the country.D. Improved transportation management and enhanced disease control contributed to China’s population explosion.E. The increase in China’s food supply, which affected population growth, was the result of technological developments in agriculture and capital investment.F. A steady increase in foreign trade since the 1400s provided the conditions necessary for largescale agricultural development.Termite IngenuityTermites, social insects which live in colonies that, in some species, contain 2 million individuals or more, are often incorrectly referred to as white ants. But they are certainly not ants. Termites, unlike ants, have gradual metarnorphosis with only three life stage: egg, nymph, and adult. Ants and the other social members of their order, certain bees and wasps, have plete metarnorphosis in four life stages。 egg, larva, pupa, and adult. The worker and soldier castes of social ants, bees, and wasps consist of only females, all daughters of a single queen that mated soon after she matured and thereafter never mated again. The worker and soldier castes of termites consist of both males and females, and the queen lives permanently with a male consort.Since termites are small and softbodied, they easily bee desiccated and must live in moist places with a high relative humidity. They do best when the relative humidity in their nest is above 96 percent and the temperature is fairly high, an optimum of about 79176。F for temperate zone species and about 86176。F for tropical species. Subterranean termites, the destructive species that occurs monly throughout the eastern United States, attain these conditions by nesting in moist soil that is in contact with wood, their only food. The surrounding soil keeps the nest moist and tends to keep the temperature at a more or less favorable level. When it is cold in winter, subterranean termites move to burrows below the frost line.Some tropical termites are more ingenious engineers, constructing huge aboveground nests with builtin “air conditioning” that keeps the nest moist, at a constant temperature, and well supplied with oxygen. Among the most architecturally advanced of these termites is an African species, Macroternes natalensis. Renowned Swiss entomologist Martin Luscher