A、The problems of poorest countries. B、The population problems in developing countries. C、Problems caused by low birth rate. D、B

In 2010, the global population reached 6.9 billion, with nearly all the growth in the world’s developing countries. According to the report, the world’s poorest developing countries account for 20 million of the 80 million people being added to the global population every year. Carl Haub, lead author of the Data Sheet, says by 2050, population growth in Africa alone will boost world numbers by one billion, assuming that birth rates today are declining on that continent and continue to do so. But he also predicts that birth rates in developing countries will eventually decline following the trend in industrialized nations. Yet, as the Data Sheet documents, Asia is expected to add the most people, about 1.3 billion, by 2050. That is likely to impose greater burdens on governments to meet the health, education and economic needs of large and young populations. In the developed world, the numbers tell a very different story. Chronically, low birth rates have created a shrinking pool of work-age people to support the wealthier countries’ elderly populations. Europe is the first region of the world to see a long-term decline in workforce. Haub says, with its much lower birth rate, Germany faces escalating problems resulting from a smaller adult workforce. And you can see that Germany already has only three people of working age for one person of the retirement age. So they have an immediate and growing crisis in their pension and health care system and they know it, for sure.
16. What can we learn about the added population in the poorest developing countries?
17. What will happen according to Carl Haub?
18. What may low birth rates lead to in developed countries?
19. What does the passage mainly tell us?