Here's why:
* Algae are primary producers: They use sunlight to convert carbon dioxide and water into glucose (sugar) and oxygen. This process, photosynthesis, stores energy in the chemical bonds of glucose.
* Fish are consumers: They cannot produce their own food. They obtain energy by eating algae (or other organisms that have consumed algae).
* Cellular respiration: Fish, like all living organisms, use a process called cellular respiration to break down the glucose from algae, releasing the stored energy to fuel their bodily functions.
Therefore, the energy released from algae during photosynthesis is ultimately used by fish through cellular respiration.
