Which of the following is a respiratory function as described in the material?

Which of the following is a respiratory function as described in the material?

• A. Intake of oxygen
• B. Production of enzymes
• C. Regulation of bone density
• D. Digestive nutrient absorption

Answer: (A)

Respiratory function centers on bringing oxygen into the body and expelling carbon dioxide to support cellular energy production. Inhaling delivers air to the lungs, where oxygen diffuses into the blood and is carried to tissues for cellular respiration. That direct role—taking in oxygen—is the respiratory function described. The other options involve different systems: producing enzymes is a metabolic/biochemical process, regulating bone density involves the skeletal and endocrine systems, and digestive nutrient absorption belongs to the digestive system. So the intake of oxygen best fits the respiratory function described.

Respiratory function centers on bringing oxygen into the body and expelling carbon dioxide to support cellular energy production. Inhaling delivers air to the lungs, where oxygen diffuses into the blood and is carried to tissues for cellular respiration. That direct role—taking in oxygen—is the respiratory function described. The other options involve different systems: producing enzymes is a metabolic/biochemical process, regulating bone density involves the skeletal and endocrine systems, and digestive nutrient absorption belongs to the digestive system. So the intake of oxygen best fits the respiratory function described.