Rewrite the given paragraph to be coherent:
The short distance is important because the capillary diffusion rate decreases when the diffusion distance increases. Because of its large number (10-14 million capillaries), there is an incredible amount of surface area for exchange.
The short distance is important because the capillary diffusion rate decreases when the diffusion distance increases. Then, because of its large number (10-14 million capillaries), there is an incredible amount of surface area for exchange.