Composition of atmosphere

The upper limit of the atmosphere is at a height of about ________ km from the mean sea level.

• 1500 km

• 1000 km

• 10,000 km

The two main gases in the atmosphere are __________ and ____________.

• Oxygen, nitrogen

• carbon-di-oxide, oxygen

• nitrogen, ozone

Heavier gases are found in this layer.

• troposphere

• mesosphere

• thermosphere

Global warming is a result of increase in __________ gases like __________.

• useful gases, oxygen

• greenhouse, carbon-di-oxide

• greenhouse, nitrogen

Water vapour and dust particles are found only in this layer.

• stratosphere

• mesosphere

• troposphere

All weather phenomena occur in this layer.

• troposphere

• stratosphere

• mesosphere

This is the coldest layer.

• thermosphere

• exosphere

• mesosphere

This gas protects from harmful ultraviolet rays of the sun.

• carbon-di0oxide

• nitrogen

• ozone

Ozonosphere is located in this layer.

• troposphere

• stratosphere

• mesosphere

Meteors burn up in this layer.

• troposphere

• thermosphere

• mesosphere