Question

1. what does gas exchange mean?

Explanation:

Gas exchange is a biological process. In living organisms, it involves the movement of oxygen and carbon - dioxide across cell membranes or respiratory surfaces. In humans and many animals, it occurs in the lungs where oxygen is taken in from the air and carbon - dioxide is released out. In plants, it happens through stomata on leaves for the intake of carbon - dioxide and release of oxygen during photosynthesis.

Answer:

Gas exchange is the process of the movement of oxygen and carbon - dioxide across cell membranes or respiratory surfaces in living organisms for respiration or photosynthesis.