Here's why:
* Photosynthesis: Plants and other photosynthetic organisms capture sunlight and use it to convert carbon dioxide and water into sugars (glucose), which provides them with energy. This process is called photosynthesis.
* Food Chain: The energy stored in the sugars produced by plants is then passed on to other organisms through the food chain. Herbivores eat plants, carnivores eat herbivores, and so on.
* Energy Flow: As energy flows through the food chain, it is transformed and some is lost as heat.
While there are a few exceptions, like ecosystems based on chemosynthesis around hydrothermal vents, the sun is the ultimate source of energy for the vast majority of life on Earth.
