Which sphere includes oxygen and carbon dioxide?

Which sphere includes oxygen and carbon dioxide?

• A. The biosphere.
• B. The atmosphere.
• C. The hydrosphere.
• D. The cryosphere.

Answer: (B)

The atmosphere is the layer of gases that surrounds Earth, and it contains the gases we breathe—oxygen—and the greenhouse gas carbon dioxide. Oxygen makes up most of the air, while carbon dioxide is present in smaller but important amounts. While some oxygen and CO2 can be dissolved in the oceans (part of the hydrosphere), in terms of what the gases are in their typical state, they are part of the atmosphere. The other spheres describe water, living things, or ice, so they don’t capture the primary gaseous form of these two substances.

The atmosphere is the layer of gases that surrounds Earth, and it contains the gases we breathe—oxygen—and the greenhouse gas carbon dioxide. Oxygen makes up most of the air, while carbon dioxide is present in smaller but important amounts. While some oxygen and CO2 can be dissolved in the oceans (part of the hydrosphere), in terms of what the gases are in their typical state, they are part of the atmosphere. The other spheres describe water, living things, or ice, so they don’t capture the primary gaseous form of these two substances.