What processes are powered by Earth's internal energy?

• A. Volcanoes, earthquakes, and mountain building
• B. Weather, climate, and ocean circulations
• C. Photosynthesis in plants
• D. Erosion and sediment transport

Answer: (A)

Energy from inside the Earth powers long-term geologic activity. The interior stays hot from leftover formation heat and ongoing radioactive decay, which drives convection in the mantle. This movement of mantle rock pushes and drags the tectonic plates, and their interactions can form mountains, cause earthquakes when rocks fracture, and drive magma to the surface as volcanoes. These processes unfold deep within the planet and operate on geological time scales.

In contrast, weather, climate, and ocean circulation are largely driven by energy from the Sun, not the planet’s interior. Photosynthesis uses sunlight, and erosion and sediment transport are surface processes powered by gravity and moving water or air, which are ultimately set in motion by solar heating of the surface.