Air cannot be ____ but can be ____ .

• felt, seen

• seen, felt

• seen, heard

• heard, seen

_________ makes us possible to fly kites

• Moving air

• Gravity

• Pressure

• None of the above

When does wind blow at a very high speed ?

• Always

• During summer times

• During a storm

• All of the above

Air is blue in colour.

• False

• True

As we move higher up , the air gets ______.

• Rarer

• Denser

• Heavier

• Lighter

Why do mountaineers carry oxygen cylinders with them, while climbing high mountains?

• As we move up air becomes denser.

• At higher altitude air is dangerous

• At higher altitude air is rarer

• None of the above

Until the eighteenth century, people thought that air was just __________ substance.

• One

• Many

When air comes in contact with a cool surface, it _________.

• Evaporates

• Solidifies

• Melts

• Condenses

Presence of water vapour in the atmosphere is important for the _________ .

• Rotation

• Water Cycle

• Precipitation

• Evaporation

________ supports burning.

• Water

• Oxygen

• Helium

• Carbon Dioxide