When you rub your cold hands together, the friction between them results in heat that warms your hands. Why doesn't warming friction result during movements of the heart, lungs and digestive organs.

The correct answer is - the presence of serous fluid.

Explanation:

Organs that show continuous movement or mobile organs like lungs, digestive organs, and the heart does not show any type of warming friction as they work.

This is due to reduced friction by the presence of serous fluid which allows the serous membranes to slide over one other. All these organs have surroundings where the serous fluid is present.