The duckweed, cattails, and other producers in a pond ecosystem have a greater total amount of energy available than the frogs, minnows, and other consumers in the same ecosystem.

Here's why:

* Producers are the base of the food chain: They capture energy from the sun through photosynthesis and convert it into usable forms (sugars).

* Consumers rely on producers: Frogs, minnows, and other consumers get their energy by eating producers or other consumers that have already consumed producers.

* Energy loss in each trophic level: Energy is lost as heat and waste at each level of the food chain (about 10% is transferred to the next level). This means that the higher up the food chain you go, the less energy is available.

Therefore, the producers have the largest total energy available because they are the primary source of energy in the ecosystem.