Temperature is considered as the most ecologically relevant environmental factor because it affects or organisms.

Options

A. physiology
B. morphology
C. geographical distribution
D. all of these

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question states that temperature is an ecologically relevant environmental factor and asks how it affects organisms.

2. **Identifying the Options**: The options provided are:
- Option 1: Physiology
- Option 2: Morphology
- Option 3: Geographical distribution
- Option 4: All of these

3. **Analyzing the Effects of Temperature**:
- **Physiology**: Temperature influences physiological processes such as metabolism, respiration, and reproduction in organisms. For example, many enzymes have optimal temperature ranges for activity.
- **Morphology**: Temperature can affect the physical form and structure of organisms. For instance, some animals may develop thicker fur in colder climates.
- **Geographical Distribution**: Temperature plays a crucial role in determining where species can live. Certain species are adapted to specific temperature ranges, which influences their distribution across different habitats.

4. **Conclusion**: Since temperature affects physiology, morphology, and geographical distribution, it is evident that all these aspects are interconnected and influenced by temperature.

5. **Selecting the Correct Answer**: Based on the analysis, the most comprehensive answer is option 4: "All of these."

**Final Answer**: The correct answer is option 4: All of these.

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