1. Water pollution and air pollution lead to the upsetting of the oxygen balance, destruction of the ozone layer, and disappearance of rare species of animals, birds, fish and plants. A number of rivers and lakes dry up. 2. Some species of animals, birds, fish and plants disappeared forever because their natural habitats were destroyed. 3. Man's careless interaction with nature can lead to ecological crisis.4. It was the most horrible ecological disaster which befell Ukraine and its people. It was caused by the accident at the Chernobyl nuclear power station in April 1986. A great damage has been done to Ukraine's agriculture, forests and people's health.5. If we want to save the world we live in, we should learn how to use the environment carefully and do our best to protect it from our destructive activities.