Fill in the blanks.

1. The envelope of gases surrounding Earth is called ___________________.
2. The _________________ of Earth holds the atmosphere in its place.
3. _______________ are boundaries between the layers of atmosphere.
4. Tropopause is the layer between Troposphere and ______________.
5. ________________ is a natural process that warms Earth's surface.
6. ________________ is the process that causes Earth's temperature to rise and make Earth warmer.

Match the following:

Write 'T' for True and 'F' for False.

1. Atmosphere is held in its place by the presence of gases.
2. Atmosphere is classified on the basis of density and temperature.
3. Meteors from space burn up in exosphere.
4. Gradual increase in Earth's temperature is known as global warming.
5. Population increase helps in reducing global warming.
6. Pollution from vehicles damages the ozone layer.
7. Air in the troposphere thins as altitude increases.

What is the percentage of oxygen in the atmosphere?

Define exosphere?