Question

select all the correct answers.
which three of the following steps in the carbon cycle describe how carbon moves between earth’s subsystems?

• when fossil fuels are burned, they release carbon dioxide into the air.
• decaying organic material buried in the crust turns into fossil fuels.
• plants use carbon dioxide in the air to perform photosynthesis.
• animals use carbon stored in plants by eating them.
• carbon dioxide in the air is dissolved in the oceans’ shallow waters.

Explanation:

1. When fossil fuels are burned...: Fossil fuels (geosphere) release CO₂ to the atmosphere (atmosphere - geosphere interaction).
2. Plants use carbon dioxide...: CO₂ from atmosphere (atmosphere) is used by plants (biosphere) - atmosphere - biosphere interaction.
3. Carbon dioxide in the air...: CO₂ from atmosphere (atmosphere) dissolves in ocean water (hydrosphere) - atmosphere - hydrosphere interaction.

The other options: "Decaying organic material..." is within the geosphere/biosphere (no subsystem shift), "Animals use carbon..." is within the biosphere (no subsystem shift).

Answer:

• When fossil fuels are burned, they release carbon dioxide into the air.
• Plants use carbon dioxide in the air to perform photosynthesis.
• Carbon dioxide in the air is dissolved in the oceans’ shallow waters.