1. Environment Kristiina Rinne Kanepi Gymnasium 9a

2.  1.What causes rain and snow? Hermann  2. Why do we need trees? Kristiina  3.What causes air pollution? Alvar  4.What is global warming? Kreete

3. Why do we need trees? Me.  Provide homes for small animals.  The wood can be made into buildings and houses.  Provide many different kinds of food for both animals and people.  Breathing.  People need timber to heat their homes.

4.  Trees also provide many different kinds of food for both animals and people, such as nuts and fruit and even the sap that gets turned into maple syrup. The roots of trees also hold on to water and soil, which helps lessen the chance of flooding in certain areas. Trees even help clean the soil and the air.

5. What causes air pollution? Alvar  Key points:  Industry  means of transport  power  farming  Human to

6.  Air pollution is caused by a wide variety of things. The earth is great at cleaning the air on its own. However, air pollution has grown so much, the earth can no longer clean all of it. This is starting to have adverse effects on the environment such as causing acid rain, smog and a wide variety of health problems.

7. What is global warming? Kreete  Key words:  Warming  Ice melts  Climate  Air

8.  Global warming is a ground-level atmosphere and the ocean temperature increases.  a moment believed that the cause of the greenhouse effect is the strengthening of human activities. the majority of human-caused global warming is due to the increase in carbon dioxide concentration.

9. References  http://et.wikipedia.org/wiki/Taimed#Taim ede_evolutsioon  http://answers.yahoo.com/question/inde x?qid=1006022206175  http://et.wikipedia.org/wiki/Fotos%C3%BC ntees