CCK (chоlecystоkinin) is а hоrmone thаt ___, whereаs GIP ____
CCK (chоlecystоkinin) is а hоrmone thаt ___, whereаs GIP ____
а swimming instructоr
Reаd the pаssаge. Then answer the questiоn. The Wоrld's Pоpulation in 2050 1 There has been huge growth in the world's population over the last 100 years. In 1930, there were 2 billion people on the planet. In 2011, the figure passed 7 billion. According to the United Nations, our population will increase to between 8 billion and 10.5 billion by 2050. The rate of increase has slowed, however. Between 1950 and 2000, the growth rate was 1.76 percent. Between 2000 and 2050, it is predicted to drop to 0.77 percent. Nevertheless, with 1.8 billion women currently of childbearing age, the growth is likely to continue for sometime. Demography experts predict that we will reach a stable rate, that is, a rate at which the current population replaces itself, in about 2030. 2 Population trends vary tremendously from one region to another. Population growth increases as a result of increases in three rates: fertility, life expectancy, and immigration. Between now and 2050, the greatest growth is expected in the developing world, particularly in Eastern and Western Africa, where fertility rates remain high. For example, it is predicted that Nigeria will go from 160 million to over 400 million. In Ethiopia, an increase from 91 million to about 278 million is predicted. 3 In contrast, the population of Western Europe and especially Eastern Europe will either grow very slowly or in some cases decline. Compare the examples of Spain and Tanzania. The size of their populations is similar; both have a current population between 46 and 48 million. In 2050, Spain's population will be about the same that it was in 2010, whereas Tanzania's population is expected to triple. 4 Although Spain's population is predicted to remain about the same, some countries in Europe are experiencing a population decrease. This occurs as a result of several factors: a fall in fertility or life expectancy, or significant migration out of the country. In most Eastern European countries, fertility rates have fallen below the replacement rate. In addition, life expectancy is lower in Easter Europe than in many other parts of the developed world. This is especially true in Russia. Finally, in several Eastern European countries, many people have left for Wester Europe or North America. 5 Among wealthy countries, the United States is somewhat unusual. It is expected to continue to grow for two reasons. It has a high immigration rate, and, compared to other countries, it has a fairly high fertility rate. Each population trend creates its own benefits and challenges. Individual governments and international organizations, such as the United Nations, take these issues seriously and will need to develop policies to manage them in the future. Why does the U.S. population have a higher rate of increase than other developed countries?