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

• the Carbon Cycle

• the Oxygen Cycle

• the Carbon dioxide Cycle

• the Water Cycle

_____________ is an essential element of all living creatures.

• Gold

• Carbon

• Carbon dioxide

• Silver

The total amount of the carbon on Earth is constant.

• True

• False

Carbon is used in the process called __________ by plants and algae to make food and the building blocks for growth.

• carbon cycle

• life

• photosynthesis

• decomposition

Bacterias that decompose dead plants release _____________ back into the atmosphere.

• water

• nitrogen

• oxygen

• carbon

In the oceans; algae, plants, and other organisms use carbon from the atmosphere for ________________.

• respiration

• decomposition

• transpiration

• photosynthesis

Organisms that die in the ocean may __________ to the bottom and form limestone rock of a period of time.

• sink

• float

• rise

• increase

Ocean coral and oysters use carbon to create _________.

• oxygen

• shells

• leaves

• food

Limestone is a type of rock created from the ______________ of dead sea organisms.

• waste

• slime

• shells

• unknown

Over ________________ of years, once-living matter that remains in the ground can transform into fossil fuels.

• millions

• hundreds

• thousands

• a few handful