Which two mechanisms are important for maintaining the steep concentration gradients of oxygen and carbon dioxide that are necessary for gas exchange?

The two mechanisms that are important for maintaining the steep concentration gradients of oxygen and carbon dioxide necessary for gas exchange are:

1. Ventilation: This is the process of moving air in and out of the lungs. It helps to maintain a high concentration of oxygen and a low concentration of carbon dioxide in the alveoli (tiny air sacs in the lungs where gas exchange occurs). When you inhale, oxygen-rich air enters the lungs and when you exhale, carbon dioxide-rich air is expelled. This constant exchange of gases ensures that the concentration gradients for oxygen and carbon dioxide are maintained.

2. Blood circulation: The circulatory system plays a crucial role in maintaining these concentration gradients. Oxygen-poor and carbon dioxide-rich blood is pumped from the body to the lungs, where it picks up oxygen and releases carbon dioxide. The oxygen-rich blood is then transported back to the body. This continuous flow of blood ensures that oxygen and carbon dioxide are constantly being exchanged, maintaining the concentration gradients.