The series of organisms taking part at various biotic levels is called

Options

A. Food chain
B. Food web
C. Ecosystem
D. Biome

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term that describes a series of organisms that participate at various biotic levels.

2. **Identifying Key Terms**: The key terms in the question are "series of organisms" and "biotic levels". This indicates that we are looking for a concept that involves different organisms interacting in an ecological context.

3. **Defining Biotic Levels**: Biotic levels refer to the different levels of organisms in an ecosystem, which can include producers (like plants), herbivores (plant-eating animals), carnivores (meat-eating animals), and decomposers (organisms that break down dead matter).

4. **Connecting to the Concept**: The series of interactions among these organisms, where one level is consumed by the next, is what we refer to in ecology.

5. **Identifying the Correct Term**: The correct term for this series of organisms is "food chain". A food chain illustrates how energy and nutrients flow from one organism to another in an ecosystem.

6. **Conclusion**: Therefore, the answer to the question is that the series of organisms taking part at various biotic levels is called a "food chain".

**Final Answer**: The series of organisms taking part at various biotic levels is called a **food chain**.

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