What is the primary function of the respiratory system?

• A. To facilitate the exchange of oxygen and carbon dioxide between the body and the environment
• B. To produce hormones that regulate metabolism
• C. To transport nutrients throughout the body
• D. To break down food into absorbable molecules

Answer: (A)

Verified step by step guidance

1. Step 1: Begin by identifying the primary role of the respiratory system in the human body. The respiratory system is responsible for gas exchange, specifically oxygen intake and carbon dioxide removal.
2. Step 2: Understand the process of gas exchange. Oxygen is inhaled into the lungs, where it diffuses into the bloodstream, and carbon dioxide, a waste product of cellular respiration, is exhaled.
3. Step 3: Compare the functions listed in the question. The respiratory system does not produce hormones, transport nutrients, or break down food; these are functions of other systems like the endocrine, circulatory, and digestive systems.
4. Step 4: Focus on the correct function: facilitating the exchange of oxygen and carbon dioxide between the body and the environment. This is the unique and primary role of the respiratory system.
5. Step 5: Conclude that the correct answer is the first option: 'To facilitate the exchange of oxygen and carbon dioxide between the body and the environment.'