– Všetko čo študent potrebuje
Utorok, 23. septembra 2014
Dátum pridania:08.05.2004Oznámkuj:12345
Autor referátu:kikabubu
Jazyk:AngličtinaPočet slov:605
Referát vhodný pre:Stredná odborná školaPočet A4:2
Priemerná známka:2.98Rýchle čítanie:3m 20s
Pomalé čítanie:5m 0s

The environment means surroundings in which people, animals and plants exist.
Ecology is a branch of biology which investigate relationships between living beings and their environment.

The most serious ecological problems of today are:
Ř the pollution of air, water and soil,
Ř the destruction of ecosystem,
Ř disappearance of many species of animals and plants,
Ř the weather changes,
Ř acid rains,
Ř the warming up of the Earth´h surface,
Ř the destruction of tropical rain forests,
Ř breaking of the ozone layer.

The growing number of cars contribute much to the air pollution. Factories, power stations and motor vehicles pump large quantities of carbon dioxide and other waste gases into the air. Factories also pollute rivers because they put there their chemical waste. Also farmers pollute the soil using a lot of pesticides and fertilizers. This pollution can also poison groundwater.

Acid rain:
Acid rain is caused by emissions of sulphur dioxide and nitrogen oxides. Some of them in combination with water make sulfuric acid in the clouds, it later falls as acid rain which kills trees and make soil infertile.

Global warming and green house effect:
In the last 100 years the Earth´s surface has warmed up by more than half a degree. Very small changes in the Earth´s climate can cause very big problems – sea levels rise up. Global warming is caused by the greenhouse affect. A major cause of the green house effect is polluted atmosphere by carbon dioxide from fossil fuels (oil, gas) and chlorofluorocarbons, which are found in refrigerators and aerosol sprays. Normally, heat from the sun warms the earth and then escapes back into space. But carbon dioxide and other gases in the atmosphere trap the sun´s heat, and this is slowly making the earth warmer. Deforestation:
Man has destroyed many tropical rain forests, which are so important for the Earth´s climate. They help to control global warming because they absorb carbon dioxide.

The ozone layer:
The ozone layer is a layer of gas high above the surface of the earth that helps to protect it from the sun´s ultraviolet radiation, which can damage our skins and cause cancer.
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