Which is a function of the respiratory system?

Which is a function of the respiratory system?

• A. Moves air in and out of the lungs
• B. Produces digestive enzymes
• C. Filters blood
• D. Removes carbon dioxide from the body by breathing

Answer: (D)

The essential role of the respiratory system is to exchange gases: bring oxygen into the body and remove carbon dioxide produced by metabolism. The key function described is removing carbon dioxide from the body by breathing, because this waste gas must be expelled to keep blood pH balanced and to maintain proper metabolic function. Breathing in and out is the mechanism that enables this gas exchange, but the critical outcome is getting rid of CO2. The other options point to functions of other body systems, such as digestion and blood filtration, which are not performed by the respiratory system.

The essential role of the respiratory system is to exchange gases: bring oxygen into the body and remove carbon dioxide produced by metabolism. The key function described is removing carbon dioxide from the body by breathing, because this waste gas must be expelled to keep blood pH balanced and to maintain proper metabolic function. Breathing in and out is the mechanism that enables this gas exchange, but the critical outcome is getting rid of CO2. The other options point to functions of other body systems, such as digestion and blood filtration, which are not performed by the respiratory system.