Two different species cannot live for long duration in the same niche or habitat. This law is

Options

A. Allen's law
B. Gause's law
C. Competitive exclusion principle
D. Weiseman's theory

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question states that two different species cannot coexist for a long duration in the same niche or habitat. This concept is fundamental in ecology and relates to how species interact with each other and their environment.

2. **Identifying the Options**: The options provided are:
- Allen's law
- Gauss law
- Competitive exclusion principle
- Weismann theory

3. **Analyzing Each Option**:
- **Weismann Theory**: This theory, proposed by August Weismann, focuses on the germplasm and inheritance but is not directly related to species competition in niches.
- **Allen's Law**: This law pertains to the physical adaptations of organisms in different climates, specifically regarding body size and shape, and does not address niche competition.
- **Gauss Law and Competitive Exclusion Principle**: These two terms refer to the same principle. The competitive exclusion principle states that two species competing for the same resources cannot coexist indefinitely. One species will outcompete the other, leading to the exclusion of the less competitive species.

4. **Conclusion**: The correct answer to the question is the **Competitive Exclusion Principle**, which explains that two different species cannot live for a long duration in the same niche or habitat due to competition for limited resources.

**Final Answer**: Competitive Exclusion Principle

---