Which statement is true regarding convection?

Convection is a heat transfer process that occurs in fluids, which include liquids and gases. This process involves the movement of warmer portions of the fluid rising while cooler portions sink, creating a circular motion known as a convection current.

The requirement of a fluid is fundamental because convection relies on the ability of particles to move and carry energy with them. In solids, the particles are held tightly in place and cannot flow; thus, convection cannot occur. This makes the statement about convection requiring fluids to take place true and highlights why it is the correct answer.

In relation to temperature changes, convection is often driven by differences in temperature within the fluid, which creates density variations. As the temperature rises, the fluid expands, becomes less dense, and rises, while cooler, denser fluid sinks. Therefore, the idea that convection does not depend on temperature changes is not accurate.

Overall, understanding convection in the context of fluids is essential for grasping how heat transfer works in everyday phenomena, such as boiling water or atmospheric circulation.