Air (Set 1)

Our Earth is surrounded by a layer of air known as ______________.

• atmosphere

• water vapor

• sky

______________ is a mixture of different gases.

• Air

• Water

• Soil

Which gas form has the largest component of air?

• nitrogen

• carbon dioxide

• oxygen

Nitrogen is ____ percent of the air.

• 78

• 21

• 1

Oxygen is ____ percent of the air.

• 78

• 21

• 1

Other gases is ____ percent of the air.

• 78

• 21

• 1

Which gas is used to make fertilizers?

• nitrogen

• oxygen

• noble gases

Which gas is used to make explosives?

• nitrogen

• oxygen

• noble gases

_________ is an important gas for all living things. Without it, living things cannot survive.

• helium

• carbon dioxide

• oxygen

We breathe in ______. Our body needs it to produce energy from the food we eat.

• dust and microorganisms

• oxygen

• carbon dioxide