题目内容：

A rising population is one of the main reasons that there is global warming. Between 1650 and 1850 the population increased by 0.75 billion people going from 0.25 billion to one billion. From 1930 to the end of the century the population rose from two billion to over six billion. In just a third of the time the population rose by more than five times what it did before. It is expected that this trend in the changing population will continue and could even heighten. The growing population requires increasing amounts of energy. These energy demands and other supplies require production, which almost always involves the emission of greenhouse gases. The more the population increases the more greenhouse gases that are produced and the greater the increase in temperature.

The burning of fossil fuels is one of the best-known causes for global warming. The major reason for fossil fuels contributing so much to global warming is the release of carbon that occurs during the burning of fossil fuels. When people burn fossil fuels, they release large amounts of carbon by way of the release of carbon dioxide. The carbon dioxide in the air then leads to global warming.

Another source of carbon dioxide comes from deforestation. In forests there is a large amount of carbon that is stored in the trees and other plants. This carbon is out of the atmosphere because the trees consume the carbon from carbon dioxide. When people cut down trees, they are frequently burned. This burning releases the carbon dioxide into the atmosphere that was stored in organic matter. Even when new trees are planted, it can take up to one hundred years to make up for the carbon that was released. It is commonly thought that because trees absorb more carbon dioxide, the atmosphere experiences positive effects.

Sophie Armstrong, the writer of Earth Care put it, “There’s no doubt that the earth is becoming warmer because of human activity rather than a random but natural phenomenon.

1.Which of the following titles goes with the text?

A. A Rising Population

B. Saving Sources of Energy

C. Global warming: The causes

D. Carbon Dioxide

2.The underlined word “deforestation” means________ .

A. rising population   B. burning of fossil fuels

C. greenhouse gas      D. cutting down or burning trees.

3.To sum up from the passage, it is_________  that has caused global warming.

A. human activity      B. sources of energy

C. natural forces      D. the polluted atmosphere

4.Which column of a website might the passage come from?

A. Economy.   B. Art    C. Environment  D. Health