How do plants affect the air that animals and people breathe?

• Plants take in oxygen and release carbon dioxide

• Plants use oxygen from the air to make their own food

• Plants take in carbon dioxide and release oxygen

• Plants release pollution into the air

The circulation of the element Carbon among Earth's atmosphere, land, oceans, and organisms is called

• the Carbon dioxide Cycle

• the Carbon Cycle

• the Water Cycle

• The cycle of life

Combustion is another word for

• life cycle

• dying

• burning

• plants

How do living organisms return carbon to the atmosphere in the carbon cycle?

• decomposition and respiration

• respiration and photosynthesis

• only decomposition

• only photosynthesis

All of the carbon in existence is continually recycled in the carbon cycle

• true

• false

Carbon enters the soil through dead plant or animal matter.

• precipitation

• Photosynthesis

• Respiration

• Decomposition

What does NOT produce carbon dioxide?

• Animal respiration

• Burning Fossil Fuels

• Photosynthesis

• Plants decaying

When humans burn fossil fuels, most of the carbon quickly enters the _______________________ as carbon dioxide.

• Atmosphere

• Ground

• sun

• rocks

What organisms in the ocean absorb the most carbon dioxide?

• coral

• sharks

• Algae and marine plants

• fish

If the plant population decreased, the amount of carbon in the atmosphere would ____________________.

• decrease

• increase

• no change would happen