1. DANGERS TO THE ENVIRONMENT 1. The environment People affect the environment. The environment also affects people. Some human activities, such as agriculture, construction and hunting, can be harmful to the environment. 2. Pollution Pollution is the contamination of air, soil or water. The combustion of oil or coal pollutes the air. Insecticides pollute the soil. Urban and industrial waste pollutes rivers and oceans. Pollution can change ecosystems. 3. Global warming Carbon dioxide in the atmosphere maintains heat on the Earth. Life on Earth is possible thanks to this heat. The atmosphere lets light in but does not let heat out.This is called the greenhouse effect. There is much more carbon dioxide in the atmosphere now. Consequently, the Earths temperature is increasing because more heat is retained in the atmosphere. This is called global warming. 4. Extinction Pollution and global warming can cause species to become extinct. Today many species are endangered. All species depend on other species in food chains. Consequently, if one species becomes extinct, other species can become extinct too. 2. Circle the correct alternative in each of the following sentences: 1. People affect / do not affect the environment. 2. Agriculture, construction and hunting can / can't be harmful to the environment. 3. The greenhouse effect occurs when the atmosphere does not let heat in / out. 4. There is much more / less carbon dioxide in the atmosphere now. 5. The Earth's temperature is increasing /decreasing. 6. Today many / few species are endangered.