Which happens as part of the convection cycle in earth's atmosphere?

a. hot, denser air rises.
b. hot, less less-dense air falls.
c. cold, denser air falls.
d. cold, less-dense air falls.

The answer is C. Cold, denser air falls

Convection is a process of transmission of heat by transporting molecules from place to place within a substance. It occurs in in fluids that moves freely such as water and air. In the atmosphere, convection is the rising and falling of air masses. In convection, the hot, less dense air at the equator rises and cool, dense air at the poles falls and moves toward the equator.