A class uses an aquarium that contains sand, water, snails, and Elodea plants to model the cycling of carbon through ecosystems. The students put the aquarium in a location where it receives plenty of natural light. Bubbles form near the plant leaves. The snails glide over the sand and eat the plants. Over time, the snails and plants grow larger. Which observation provides evidence that carbon from sugars produced during photosynthesis is used to build larger molecules? OA. The plants grow when they are underwater. B. The snails grow larger after they eat the plants. C. The snails glide over the sand and grow larger. A D. The aquarium is in a location that gets plenty of natural sunlight.
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