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 Role of Temperature**:
- Temperature is a crucial environmental factor that influences various aspects of an organism's life. It affects their physiological processes, behavior, and overall survival.

2. **Physiological Effects**:
- Temperature impacts the metabolic rates of organisms. For example, higher temperatures can increase metabolic rates, while lower temperatures can slow them down. This affects how organisms grow, reproduce, and respond to environmental changes.

3. **Morphological Adaptations**:
- Organisms have different physical structures that help them survive in varying temperatures. For instance, animals in colder climates often have thicker fur or feathers for insulation, while those in warmer climates have thinner fur or feathers to help dissipate heat.

4. **Behavioral Adaptations**:
- Temperature influences the behavior of organisms, including their feeding habits and migration patterns. For example, many bird species migrate to warmer regions during winter to find food and suitable living conditions.

5. **Geographical Distribution**:
- The distribution of species across different geographical areas is largely determined by temperature. Certain species thrive in specific temperature ranges, which influences where they can live and reproduce.

6. **Conclusion**:
- Given all these points, temperature is indeed considered the most ecologically relevant environmental factor because it affects physiological processes, morphological adaptations, behavioral patterns, and geographical distribution of organisms.