CH.2 Importance & structure of Atmosphere

__________ per cent of the atmosphere is composed of oxygen

• 76
• 21
• 1
• 99

The ___________ (layer of the atmosphere) contains 99 per cent of water vapour

• troposphere
• stratosphere
• mesosphere
• exosphere

The meteorites burn up in the ____________________-

• stratosphere
• mesosphere
• thermosphere
• exosphere

The International Space Station orbits the Earth within _________

• troposphere
• stratosphere
• mesosphere
• thermosphere

The ___________ is the outermost layer of the earth's athmosphere

• exosphere
• thermosphere
• mesosphere
• stratosphere