Which of the following statements is correct?

Options

A. Two species within a given community can have exactly the same niche.
B. Two species within a given community cannot have exactly the same niche.
C. Two species can live permanently together
D. Both (2) and (3).

Answer

To determine which statement is correct regarding species and their niches, we can analyze the options provided based on ecological principles.

### Step-by-Step Solution:

1. **Understand the Concept of Niche**: A niche refers to the role or function of an organism or species within an ecosystem, including its habitat, resource use, and interactions with other organisms.

2. **Review the Competitive Exclusion Principle**: This principle states that two species competing for the same resources cannot coexist if their niches are identical. If they do occupy the same niche, one species will outcompete the other, leading to the exclusion of the less competitive species.

3. **Analyze the Options**:
- **Option 1**: "Two species within a given community can have exactly the same niche."
- This contradicts the competitive exclusion principle, as it suggests that two species can coexist with identical niches.
- **Option 2**: "Two species within a given community cannot have exactly the same niche."
- This aligns with the competitive exclusion principle, indicating that two species cannot occupy the same niche simultaneously.
- **Option 3**: "Two species can live permanently together."
- This is not necessarily true, as it depends on their niches. If their niches overlap significantly, one may outcompete the other.
- **Option 4**: "Both two and three."
- Since option 3 is not correct, this option cannot be correct either.

4. **Conclusion**: Based on the analysis, the correct statement is **Option 2**: "Two species within a given community cannot have exactly the same niche."

### Final Answer:
The correct statement is: **Option 2: Two species within a given community cannot have exactly the same niche.**