When exercise increases, so does the breathing rate. This helps return the person to homeostasis. An image of an alveolus, a microscopic part of the lung, is shown here. What describes how increased breathing helps return the individual to homeostasis?

1. Increased breathing rate allows for more oxygen gas to diffuse into the bloodstream, which can be delivered to muscle cells.

2. Increased breathing rate increases the conversion of carbon dioxide into glucose, which can be used to provide energy to the heart.

3. Increased breathing rate allows for faster active transport of glucose into the blood, which can be used to energize the muscle cells.

4. Increased breathing rate allows for more carbon dioxide to be moved into the bloodstream via facilitated diffusion, which can be delivered to the heart, which is beating faster.