Convection currents are considered to occur in which part of the Earth?

Correct answer: Mantle

The direct answer is C: convection currents are mainly considered to occur in the mantle. The mantle is the thick layer inside Earth between the crust and the core. Deep mantle material is heated from below. Hot material becomes less dense and tends to rise, while cooler material becomes denser and tends to sink. This movement forms convection currents and is used to explain internal Earth movement and, in older geographical explanations, plate movement. Option C is correct because the mantle is the relevant solid-but-plastic internal layer. Option A is wrong because convection can occur in the atmosphere, but this question concerns the geological theory of Earth’s interior. Option B is wrong because a river bed is a surface feature, not the source of these planetary currents. Option D is wrong because a glacier is surface ice and is unrelated to mantle convection. Memory cue: for Earth’s internal convection, think heated mantle rising and cooled material sinking.