Final answer:
The primary source of energy in a food chain is the sun. Plants are the primary producers and obtain energy from the sun through photosynthesis.
Step-by-step explanation:
The primary source of energy in a food chain is the sun.
Plants are the primary producers in a food chain, and they obtain energy from the sun through the process of photosynthesis. They convert sunlight into chemical energy in the form of glucose.
Animals in the food chain then obtain energy by consuming plants or other animals that have consumed plants.
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