Energy enters in a food chain through:

Options

A. primary consumers
B. secondary consumers
C. tertiary consumers
D. producers

Answer

**Step-by-Step Solution:**

1. **Understanding the Food Chain**: A food chain is a sequence that shows how energy and nutrients flow through an ecosystem. It typically starts with producers, followed by consumers, and then decomposers.

2. **Identifying Producers**: Producers are organisms that can make their own food using sunlight, water, and carbon dioxide through the process of photosynthesis. Examples include plants, algae, and some bacteria.

3. **Role of Producers in Energy Transfer**: Producers are the first level in the food chain. They convert solar energy into chemical energy in the form of glucose, which serves as food for themselves and for other organisms in the ecosystem.

4. **Conclusion**: Since producers are the ones that create food and energy in the ecosystem, we can conclude that energy enters a food chain through producers.

**Final Answer**: Energy enters a food chain through producers.

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