Bài IV.
Nowadays , environmentalists are so worried about environmental problems that can directly affect people’s life . Among the problems mentioned every day on mass media , air pollution and water pollution are considered the most serious ones .
There are many factors that cause the pollution of the air : chemicals from burned fuels, smoke from automobiles , and acid rain from chemical transformation . Smoke can cause serious health problems while acid rain is responsible for the destruction of many forest ecosystems .
Raw sewage , garbage , and oil contribute to the pollution of water . When water is polluted , it cause a lot of waterborne diseases and threatens marine wildlife . About 1.5 billion people around the world lack safe drinking15 meters or more . A tsunami always has tremendous energy because of the great amount of water . It can destroy all settlements along the coast and cause plenty of deaths and property damage .