What is one of the roles of the respiratory system?

The respiratory system is primarily responsible for facilitating breathing and enabling gas exchange within the body. This vital function involves the inhalation of oxygen from the atmosphere and the exhalation of carbon dioxide, a waste product of metabolic processes. The oxygen absorbed into the bloodstream is essential for cellular respiration, allowing cells to produce energy efficiently. Additionally, the respiratory system helps maintain the proper balance of oxygen and carbon dioxide levels in the blood, which is crucial for sustaining life. This role is distinct from other bodily systems, such as the digestive system, which is responsible for nutrient absorption, or the endocrine system, which regulates hormone levels affecting blood sugar. Thus, choice C accurately reflects a fundamental function of the respiratory system.