How much energy is passed from one trophic level to the next trophic level.

Explanation

### Step-by-Step Solution:

1. **Understanding Trophic Levels**: Trophic levels refer to the different stages in a food chain, where each level represents a different group of organisms that share the same function in the ecosystem. The primary levels are producers, primary consumers, secondary consumers, and apex consumers.

2. **Energy Transfer in Ecosystems**: In an ecosystem, energy is transferred from one trophic level to the next as organisms consume one another. However, not all the energy is passed on; a significant portion is lost.

3. **Energy Loss**: It is generally accepted that only about 10% of the energy from one trophic level is transferred to the next level. This means that when a primary consumer eats a producer, only about 10% of the energy stored in the producer is available to the primary consumer.

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