Choose the odd one out with respect to the functional aspects of ecosystem.

Options

A. Energy flow
B. Decomposition
C. Species composition
D. Nutrient cycling

Answer

To solve the question "Choose the odd one out with respect to the functional aspects of ecosystem," we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding Ecosystem Functions**:
- An ecosystem has various functional aspects that include energy flow, nutrient cycling, decomposition, and species composition. Each of these plays a role in maintaining the balance and health of the ecosystem.

2. **Analyzing Each Option**:
- **Option 1: Energy Flow**
- Energy flow in an ecosystem is unidirectional. It starts from the sun, moves to producers (plants), and then to consumers (herbivores and carnivores). This is a fundamental aspect of ecosystem functioning.

- **Option 2: Decomposition**
- Decomposition is the process by which dead organic matter is broken down into simpler organic and inorganic substances. It is crucial for nutrient cycling but is more of a process than a functional aspect of the ecosystem as a whole.

- **Option 3: Species Composition**
- Species composition refers to the variety and abundance of different species in an ecosystem. It is important for biodiversity and affects ecosystem stability and functioning.

- **Option 4: Nutrient Cycling**
- Nutrient cycling involves the movement and exchange of nutrients within the ecosystem, which is vital for sustaining life and maintaining ecosystem health.

3. **Identifying the Odd One Out**:
- Upon analyzing the options, we can see that:
- Energy flow, species composition, and nutrient cycling are all integral functional aspects of an ecosystem.
- Decomposition, while important, is a process that contributes to nutrient cycling and is not a direct functional aspect like the others.

4. **Conclusion**:
- Therefore, the odd one out with respect to the functional aspects of the ecosystem is **Option 2: Decomposition**.

### Final Answer:
**Option 2: Decomposition**

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