更多"With rapid growth of world populati"的相关试题:
[单项选择]With rapid growth of world population, mainly in developing countries, the available cultivable land per person has declined steadily since 1960 and will decease by half over the next 50 years. Besides, about 400 million women of childbearing age are iron deficient, leaving their babies exposed to various birth defects. As many as 100 million children suffer from vitamin A deficiency. Tens of millions of people suffer from other major ailments and nutritional deficiencies caused by lack of food.
How can biotech help Biotechnologists have developed genetically modified rice fortified with beta carotene (β-胡萝卜素) and additional iron, and they are working on other kinds of nutritionally improved crops. Biotech can also improve farming productivity in places where crop failures are caused by pests, drought, poor soil and crop viruses, bacteria or fungi. Genetically modified, virus-resistant crops can reduce that damage, as can drought-tolerant seeds in regions where water shortages
A. crop failure
B. poverty
C. food shortage
D. eco-damage
[单项选择]The rapid growth of the world’s population over the past 100 years have led to a great increase in the acreage of land under cultivation.
[填空题]The highest rate of world population growth occurred in 1970.
[单项选择]Until recently, most population growth has occurred in relatively dense urban environments. In (31) words, even if we were witnessing rapid population growth, that would not mean that the (32) were filling in with people. (33) , the urban areas would tend to become more crowded. Historically, we find that people have moved to (34) the jobs were. Jobs were usually in ports or locations with many natural (35) . After transportation became relatively cheap, other geographical locations became (36) of economic activity. One factor that determines where people will move to, even when transportation becomes cheap, is (37) . And individuals working in cities (38) higher incomes than those working in (39) areas. Hence, population has tended until the 1970s to (40) in our major urban centers.
Recently population has (41) out of the Northeast to the South and to the West for the more pleasant climates. If people di
A. dense
B. desert
C. urban
D. rural
