1. D. natural resources
⇒ Dẫn chứng: We are using up all of our natural resources.
2. B. population growth
⇒Dẫn chứng: Population. Most problems of the environment come from population growth.
3. A. having things in the right places at the right time
⇒Dẫn chứng:Scientists say there is enough water in the world for everyone, but some countries have a lot of water and some have only a little. Some areas get all their rain during one season. The rest of the year is dry. There are huge forests in the Amazon area of Brazil. In other parts of the world, there is only a desert.
4. B. They don’t have enough land to let some of it rest each year.
⇒Dẫn chứng: Poverty. Poor farmers use the same land over and over. The land needs a rest so it will be better next year. However, the farmers must have food this year.
5. C. We control the future.
⇒Dẫn chứng: The people and the nations of the world must work together to conserve the world’s resources. No one controls the future, but we can help make it.