Find the incorrect statement.

Options

A. In terrestrial ecosystems larger fraction of energy flow occurs through DFC.
B. Pyramid of energy is always upright .
C. In comparison to food chains , food webs are more stable .
D. Detritus food chain is not at all connected with aquatic food chain at any level .

Answer

To solve the question of finding the incorrect statement, we will analyze each statement provided in the context of ecosystems, particularly focusing on terrestrial ecosystems, food chains, and food webs.

### Step-by-Step Solution:

1. **Analyze the First Statement**:
- "In terrestrial ecosystems, a large fraction of energy flows through the detritus food chain."
- **Evaluation**: This statement is correct. In terrestrial ecosystems, detritus food chains, which involve decomposers breaking down organic matter, play a significant role in nutrient cycling and energy flow.

2. **Analyze the Second Statement**:
- "Pyramid of energy is always upright."
- **Evaluation**: This statement is also correct. The pyramid of energy is always upright because energy decreases as it moves up trophic levels, and it cannot be inverted.

3. **Analyze the Third Statement**:
- "In comparison to food chains, food webs are more stable."
- **Evaluation**: This statement is correct. Food webs, being more complex and interconnected than food chains, provide greater stability to ecosystems.

4. **Analyze the Fourth Statement**:
- "Detritus food chain is not at all connected with aquatic food chain at any level."
- **Evaluation**: This statement is incorrect. The detritus food chain is indeed connected with aquatic food chains, as decomposers play a crucial role in both terrestrial and aquatic ecosystems, recycling nutrients.

5. **Conclusion**:
- The incorrect statement among the options is: "Detritus food chain is not at all connected with aquatic food chain at any level."

### Final Answer:
The incorrect statement is: "Detritus food chain is not at all connected with aquatic food chain at any level."

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