Read the following statements.
(i) Removal of tigers from an area will result in increased growth of vegetation of that area.
(ii) Organisms at each trophic level depend on those at the lower trophic level for their energy demands.
(iii) Food chains are sustained by producers and decomposers
(iv) In a food chain , some organism like sparrow operates at one trophic level only.
Select an option which shows CORRECT statements.

Options

A. (i) and (ii)
B. (ii) ad (iv)
C. (ii) and (iii)
D. (i) , (iii) and (iv)

Answer

To solve the question, we need to evaluate each of the provided statements regarding ecological concepts related to food chains and trophic levels.

### Step-by-Step Solution:

1. **Evaluate Statement (i)**:
- **Statement**: Removal of tigers from an area will result in increased growth of vegetation of that area.
- **Analysis**: This statement is incorrect. Tigers are apex predators and play a crucial role in controlling herbivore populations (like deer). If tigers are removed, herbivore populations will increase unchecked, leading to overgrazing and ultimately a decrease in vegetation growth.

2. **Evaluate Statement (ii)**:
- **Statement**: Organisms at each trophic level depend on those at the lower trophic level for their energy demands.
- **Analysis**: This statement is correct. In a food chain, each trophic level relies on the one below it for energy. For example, herbivores depend on plants (producers) for energy, and carnivores depend on herbivores for their energy needs.

3. **Evaluate Statement (iii)**:
- **Statement**: Food chains are sustained by producers and decomposers.
- **Analysis**: This statement is also correct. Producers (like plants) create energy through photosynthesis, and decomposers (like fungi and bacteria) break down dead organic matter, returning nutrients to the soil, which supports producers. Both are essential for the sustainability of food chains.

4. **Evaluate Statement (iv)**:
- **Statement**: In a food chain, some organisms like sparrow operate at one trophic level only.
- **Analysis**: This statement is incorrect. Sparrows can occupy different trophic levels depending on their diet. They can be primary consumers when eating seeds and secondary consumers when eating insects, demonstrating that they can operate at multiple trophic levels.

### Conclusion:
Based on the evaluations:
- **Correct Statements**: (ii) and (iii)
- **Incorrect Statements**: (i) and (iv)

The option that shows the correct statements is **(ii) and (iii)**.