Which of the following is not entirely true fact?

Options

A. Competition occurs only when closely related species compete for the same resources that are limiting
B. Totally unrelated species could compete for the same resource
C. Resources need to be limiting for competition to occur, in interference competition, the feeding efficiency of one species might be reduced due to the interfering and inhibitory presence of the other species, even if resources are plenty
D. A complex interplay of interspecific interactions and environmental variability characterizes community structure

Answer

To determine which statement is not entirely true, we will analyze each statement provided in the question step by step.

### Step 1: Analyze the First Statement
The first statement claims that "competition occurs only when closely related species compete for the same resources that are limited."
- **Evaluation**: This statement is incorrect because competition can occur between unrelated species as well. While closely related species may compete for similar resources, unrelated species can also compete for the same limited resources. Thus, this statement is not entirely true.

### Step 2: Analyze the Second Statement
The second statement states that "totally unrelated species could also compete for the same resources."
- **Evaluation**: This statement is correct. Unrelated species can and do compete for the same resources, especially when those resources are limited. Therefore, this statement is entirely true.

### Step 3: Analyze the Third Statement
The third statement mentions that "resources need to be limiting for competition to occur in inter-specific competition."
- **Evaluation**: This statement is partially true. While limited resources often drive competition, it is possible for competition to occur even when resources are abundant, due to dominance or interference from one species over another. Therefore, this statement is not entirely true.

### Step 4: Analyze the Fourth Statement
The fourth statement discusses "a complex interplay of inter-species interaction and environmental variability characterizes community structure."
- **Evaluation**: This statement is true. Community structure is indeed influenced by various interactions among species and environmental factors. Thus, this statement is entirely true.

### Conclusion
Based on the evaluations:
- The first statement is not entirely true.
- The third statement is also not entirely true.
- The second and fourth statements are entirely true.

The correct answer to the question "Which of the following is not entirely true fact?" is the first statement.