system
Answer the question or perform the task.
human
Use synonyms to simplify this passage about the ocean food chain.

Relevant data:
Phytoplankton are the foundation of the marine food web. They convert sunlight into energy, which is used by other organisms as they move up the food chain.
gpt
Tiny plants called plankton are the beginning of the ocean's food chain. They change the sun's energy into food that bigger creatures eat.