* Autotrophs are organisms that can produce their own food through photosynthesis. They use sunlight, water, and carbon dioxide to create energy.
* Pond plants are the only organism on your list that can perform photosynthesis. They have chlorophyll, the pigment that allows them to capture sunlight and convert it into energy.
* Snails, ducks, and fish are all heterotrophs. They get their energy by consuming other organisms.