What is the main source of energy for a food chain plants fish turtles and sharks?

The main source of energy for this food chain is the sun. Plants, as primary producers, capture sunlight through the process of photosynthesis and convert it into chemical energy in the form of sugars. These plants serve as the foundation of the food chain, providing nourishment for herbivorous fish. Smaller fish become food for larger fish like turtles, while sharks, being apex predators, occupy the top of the food chain. Each step of this food chain relies on the transfer of energy from lower to higher trophic levels.