Science 1038

The climate is warmer in the valley because the air is ________.

• thicker

• tighter

High places in the earth have a _______ blanket of air.

• tan

• thin

Most of the air we breathe is made of a gas called _______.

• nitrogen

• night

Another gas in the air is called ________.

• nyxogen

• oxygen

Oxygen helps people to _______.

• eat

• breathe

Carbon dioxide is a gas found in _______

• rocks

• air

• glass

Plants draw carbon dioxide from the air through tiny openings in their _______

• stem

• leaves

• flower

After the carbon dioxide and water are changed into plant food _______ is left.

• oxygen

• water

______ give off oxygen into the air.

• people

• plants

• puppies

People and ______ breathe in oxygen and breathe out carbon dioxide.

• rocks

• plants

• animals