GEOLOGY

Detailed explanation-1: -The primary sources of thermal energy for mantle convection are three: (1) internal heating due to the decay of the radioactive isotopes of uranium, thorium, and potassium; (2) the long-term secular cooling of the earth; and (3) heat from the core.

Detailed explanation-2: -The heat that drives mantle convection comes from radioactive decay of elements within the core and mantle. This radioactive decay releases lots of energy and this energy causes those parts of the earth to become hot.

Detailed explanation-3: -Heat from the core and the mantle itself causes convection currents in the mantle. Hot columns of mantle material rise slowly. At the top of the asthenosphere, the hot material spreads out and pushes the cooler material out of the way. This cooler material sinks back into the mantle.

Detailed explanation-4: -heat from the core and the mantle itself causes convecton currents in the mantle.

Detailed explanation-5: -The sun is the external source of energy that causes convection currents, which drive the winds, ocean currents, and the water cycle.