What is gas exchange primarily responsible for?

Gas exchange is primarily responsible for providing oxygen to the bloodstream and removing carbon dioxide. This fundamental process occurs in the lungs, specifically within the alveoli, where oxygen from inhaled air diffuses across the alveolar membrane into the capillaries and binds to hemoglobin in red blood cells. At the same time, carbon dioxide—produced as a waste product by cells during metabolism—diffuses from the blood into the alveoli to be expelled from the body during exhalation. This exchange is crucial for maintaining the oxygen levels necessary for cellular respiration and for regulating carbon dioxide levels in the blood, which is vital for maintaining the body's acid-base balance.

The other choices pertain to different physiological functions that are not the primary role of gas exchange. For instance, while delivering nutrients is essential for supplying energy and building blocks to cells, it is not part of the gas exchange process. Similarly, transmitting nerve signals to stimulate respiration involves the control of breathing but is not the actual exchange of gases, and filtering air particles occurs through the respiratory system's anatomy, serving to protect the lungs rather than being involved in the gas exchange itself.