Which explanation best describes convection currents in the earth's mantle

Answer 1

Convection currents in the Earth's mantle are caused by the heat produced by the radioactive decay of elements, primarily uranium, thorium, and potassium, in the Earth's core. This heat causes the mantle to become partially molten. As the molten material near the core heats up, it becomes less dense and begins to rise towards the surface. As it rises, it cools down and becomes more dense, causing it to sink back towards the core. This circular motion of rising and sinking material creates convection currents in the mantle. These convection currents play a crucial role in the movement of tectonic plates and the formation of geological features such as mountains, volcanoes, and oceanic trenches.