Final answer:
Most of the energy used by life on Earth comes from the sun through the process of photosynthesis.
Step-by-step explanation:
Most of the energy used by life on Earth comes from the sun. Over 90% of the energy we use comes originally from the sun. Plants and many bacteria capture solar energy through photosynthesis, and we release the energy stored in plants when we burn wood or plant products. Additionally, burning coal and petroleum also releases stored solar energy.