Which statement best describes the gases involved in respiration?

Which statement best describes the gases involved in respiration?

• A. Oxygen
• B. Carbon dioxide
• C. Both oxygen and carbon dioxide
• D. Nitrogen

Answer: (C)

Gas exchange in respiration involves both oxygen and carbon dioxide. Oxygen is taken in and used by cells to produce energy through cellular respiration, while carbon dioxide is produced as a waste product and expelled from the body. In the lungs, oxygen diffuses into the blood, and carbon dioxide diffuses out into the air to be exhaled. Nitrogen largely doesn’t participate in these metabolic steps, so it isn’t part of the respiration process. That’s why describing both oxygen and carbon dioxide as involved best matches how respiration works.

Gas exchange in respiration involves both oxygen and carbon dioxide. Oxygen is taken in and used by cells to produce energy through cellular respiration, while carbon dioxide is produced as a waste product and expelled from the body. In the lungs, oxygen diffuses into the blood, and carbon dioxide diffuses out into the air to be exhaled. Nitrogen largely doesn’t participate in these metabolic steps, so it isn’t part of the respiration process. That’s why describing both oxygen and carbon dioxide as involved best matches how respiration works.