What does the term 'convection currents' refer to?

The term 'convection currents' primarily refers to the flow of air or fluid resulting from temperature differences within that medium. When a fluid, such as air or water, is heated, it becomes less dense and rises. Conversely, cooler, denser fluid will sink. This movement creates a circulation pattern known as convection currents, which is fundamental in various natural processes, including weather patterns and ocean dynamics.

The option emphasizing the flow of air due to temperature differences accurately captures the essence of convection currents, as this process occurs both in the atmosphere and in fluids such as water. The other options, while related to movement and heat, do not fully encapsulate the specific mechanism of convection currents, which relies on the interplay of temperature changes and the resulting density variations.