Which one of the following statement is incorrect?

Options

A. In amensalism one species is harmed and other is benefited.
B. Commensalism is the interaction in which one species benefits and the other is neither harmed nor benefited
C. The association of cattle egret and grazing cattle is a classic example of commensalism.
D. Competition occurs when closely related species complete for the same resources.

Answer

To determine which statement is incorrect, we will analyze each of the four statements provided in the question.

### Step-by-Step Solution:

1. **Analyze the first statement**:
- The statement claims that in Amensalism, one species is harmed and the other is benefited.
- **Correct Understanding**: In Amensalism, one species is harmed (negative impact) while the other is unaffected (neutral impact). Therefore, the first statement is incorrect.

2. **Analyze the second statement**:
- The statement describes Commensalism as an interaction where one species benefits and the other is neither harmed nor benefited.
- **Correct Understanding**: This is accurate. In Commensalism, one species gains benefits (positive impact) while the other remains unaffected (neutral impact). This statement is correct.

3. **Analyze the third statement**:
- The statement mentions that the association of cattle and grazing is a classical example of Commensalism.
- **Correct Understanding**: This is also true. The cattle provide a habitat for various organisms (like birds) that benefit from their presence without harming the cattle. Thus, this statement is correct.

4. **Analyze the fourth statement**:
- The statement indicates that competition occurs when closely related species compete for the same resources, and that both species are mainly harmed.
- **Correct Understanding**: This is accurate. In competition, both species may suffer due to resource depletion. Thus, this statement is correct.

### Conclusion:
The incorrect statement is the **first statement** regarding Amensalism.