Read the following passage and write the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions. Global warming refers to the increase of the earth's average temperature due to increasing amounts of greenhouse gases in the atmosphere. Carbon dioxide is the biggest contributor to greenhouse gas emissions. Scientists agree that the burning of fossil fuels like oil and coal causes greenhouse gases such as carbon dioxide to escape into the air and ...

Read the following passage and write the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.

Global warming refers to the increase of the earth's average temperature due to increasing amounts of greenhouse gases in the atmosphere. Carbon dioxide is the biggest contributor to greenhouse gas emissions. Scientists agree that the burning of fossil fuels like oil and coal causes greenhouse gases such as carbon dioxide to escape into the air and act like a warm blanket over the earth.

There are already some changes happening because of global warming. Sea level is rising, climate is changing, and some animals are moving to new homes because their natural habitat is disappearing. If the warming gets worse, as scientists expect, there may be some kinds of plants and animals that become extinct. Heat waves and droughts will increase, leading to wildfires, and some areas may become too dry for farming. Warmer ocean temperatures lead to more big storms which damage homes and cause floods. Sea levels may rise so much that people have to move away from the coasts.

The best way to help impede global warming and is to put less carbon into the air by using less fossil fuel - something that is easy to say, but hard to do! But by driving less, turning down the heat and air conditioning, and using more solar, wind and hydroelectric power, we can all reduce greenhouse gases and help fight global warming and climate change. What is the passage mainly about?