Choose the correct answer for each gap to complete the following passage. There are three main kinds of pollution – air pollution, water pollution, and noise pollution. Air, which is the most important element of our environment for our survival, can be polluted in many ways. Smoke in the air from mills, factories, and industry contains carbon monoxide, carbon dioxide, and methane, which are all poisonous gases. This leads to health problems like asthma and lung diseases, and the thinning of the ozone layer, which protects us from harmful UV rays. China, the USA, Russia, India, Mexico, and Japan are the world leaders in air pollution emissions. Water is also polluted by the discharge of commercial and industrial waste into surface water. Sewage in drinking water is another cause of water pollution as it contains germs and viruses. The noise of vehicles, mills, and factories can be really unbearable. This kind of constant sound also causes headaches, tension, mental stress, and migraines. People living next to a building site where there is too much noise can become sick, as they cannot sleep or relax. This is called noise pollution. 1. How many main kinds of pollution are there? ......................................................................................................................................................... 2.Which is the most important element of our environment for our survival? ......................................................................................................................................................... 3. Are China, the USA, and Japan the world leaders in air pollution emissions? ......................................................................................................................................................... 4.Why people living next to a building site where there is too much noise can become sick? .........................................................................................................................................................