Circle the correct word 5 класс workbook

Big cities are always densely populated. You will never find a city without any plant or factory. They may produce necessary goods, but at the same time they are the main air pollutors in a city. This can become a global ecological problem if we don't invent the way of cleaning the air.
Plants and factories also pollute water in rivers and lakes. A polluted river loses its "population": fish and water grass, and becomes unavailable for rest and fishing.
While I am speaking about factories I don't except that people are the city polluters too. Nowadays every fourth person owns a car, which also pollutes the air. There are some people who drop litter in parks and even in streets. This litter will not disappear immediately. (время заканчивается, сейчас добавлю остальное)

Environmental problems have become one of the most urgent problems of modern society. More and more people suffer from air and water pollution. Nature also suffers from land and nuclear pollution. The reasons for such environmental problems are numerous. Among them increasing number of cars in the streets, factory waste, millions of cut down trees, destroyed habitats of animals, contaminated rivers and seas. All these problems mainly arise due to human careless activities and gradually destroy our planet. If we look closely, we’ll notice that not only one city is under danger, but the majority of world population. Fortunately, there are many ways to suspend these problems. If everybody starts caring about the planet we live on, many environmental problems can be solved. For example, if we start recycling paper and cardboard, we can save lots of trees. If we start using public transport more than private cars, we can have less air pollution. Local governments can also help to prevent some problems, if they forbid logging companies to destroy the forests, or stop factories from polluting water. The most important thing is, of course, to start acting immediately, otherwise we might have to face many global disasters.