Carbon Cycle

Plants use CO₂ in the process of __________ to make _________ and oxygen.

• respiration, methane

• photosynthesis, sugar

• respiration, sugar

• photosynthesis, methane

Animals use oxygen in the process of ____________ to make more CO₂.

• photosynthesis

• burning of fossil fuels

• natural gas

• respiration

The __________ is the main regulator of CO₂ in the atmosphere because CO₂ dissolves easily in it.

• coal

• ocean

• natural gas

• greenhouse

In the past, huge deposits of carbon were stored as dead plants and animals ______________.

• coal

• oil

• ocean

• decayed

Today these deposits are burned as fossil fuels, which include ____________, _____________ and _____________.

• oil

• natural gas

• coal

• photosynthesis

More CO₂ is released in the atmosphere today than in the past because of the ___________________________.

• oil

• greenhouse

• burning of fossil fuels

• respiration

Another natural source for CO₂ is _____________.

• methane

• ocean

• sugar

• decayed

Too much CO2 in the atmosphere may be responsible for the _____________ effect.

• coal

• photosynthesis

• greenhouse

• ocean

What equation is shown?

• cellular respiration

• photosynthesis