IV. Read the following passage and then answer the questions below it. Air pollution is a cause of ill-health in human beings. In a lot of countries there are laws limiting the amount of smoke which factories can produce. Although there isn’t enough information on the effects of smoke in the atmosphere, doctors have proved that air pollution causes lung diseases. The gases from the exhausts of cars have also increased air pollution in most cities. The lead in petrol produces a poisonous gas which often collects in busy streets surrounded by high buildings. Children who live in areas where there is a lot of lead in the atmosphere cannot think as quickly as other children and they are clumsy when they use their hands. There are other long-term effects of pollution. If the gases in the atmosphere continue to increase, the earth’s climate may become warmer. A lot of the ice near the Poles may melt and may cause serious floods. 1. What can make people sick ? ....... 2. Where does smoke come from ? ....... 3. Can air pollution cause lung diseases ? .......... 4. What else can cause air pollution in cities ? .......... 5. Why does the earth’s climate become warmer ? ........