Which statement about energy sources is true?

• A. The Sun
• B. The Moon
• C. The Earth's core
• D. Chemical energy in fossil fuels

Answer: (A)

Energy on Earth mainly comes from the Sun. Its light and heat power weather, climate, and life, and through photosynthesis, plants capture solar energy and, over long timescales, store it as chemical energy in fossil fuels. When we burn those fuels, we release that energy. The Moon doesn’t generate energy; it just reflects sunlight. The Earth's core contains heat, and geothermal energy exists, but it’s not the primary energy source we rely on day to day. Fossil fuels do contain chemical energy, but that energy originally comes from the Sun, making the Sun the true source for virtually all energy on Earth.