Which statements best describe the phenomenon of convection?

Convection is a process involving the transfer of heat through the movement of fluids, which includes both liquids and gases. This occurs when warmer areas of a fluid rise to cooler areas, creating a cycle of movement known as a convection current. In liquids, molecules are free to move, allowing for the transfer of heat as warmer, less dense fluid rises and cooler, denser fluid sinks. Similarly, in gases, convection allows for heat distribution through movement similarly to liquids.

The other statements don't accurately capture the nature of convection. For instance, convection does not occur in solids due to their fixed structure, where heat transfer happens mainly through conduction, not movement of the material itself. Additionally, convection is a continuous process rather than a one-time event, as it relies on ongoing temperature differences within the fluid. Lastly, convection primarily transfers thermal energy rather than potential energy. Thus, the statement about convection occurring in liquids and gases accurately portrays the fundamental characteristics of convection as a thermal transfer mechanism.