Here's why:
* Photosynthesis: The sun's energy is captured by plants and algae through photosynthesis. They convert light energy into chemical energy in the form of sugars. These sugars are the basis of food chains, providing energy to herbivores and then to carnivores.
* Food Chains: The energy from the sun, stored in plants, flows through ecosystems via food chains, ultimately sustaining all life forms.
* Other Energy Sources: While some organisms (like deep-sea vent organisms) derive energy from sources other than the sun, they represent a relatively small fraction of Earth's biosphere. The sun is the primary energy source for the vast majority of life.
