Final answer:
Plants are considered primary producers because they capture energy from the sun and make it available to other organisms through photosynthesis.
Step-by-step explanation:
Plants are considered primary producers because they capture energy from the sun and make it available to other organisms. They do this through the process of photosynthesis, where they use sunlight, carbon dioxide, and water to produce glucose and oxygen. This energy-rich glucose is then used by other organisms, such as herbivores, as a source of food.
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