Which property allows for convection heating?

A

atoms are packed closely together in liquids

B

electromagnetic waves radiate out from warm objects

C

high-energy particles collide with low-energy particles in solids

D

cooler air has a higher density than warm air

Answer: D. cooler air has a higher density than warm air

Explanation: Convection is the process of heat transfer involving fluids. As a fluid absorbs heat energy its density decreases with respect to temperature. So warm air rises and cooler air sinks due to difference in density.