Ecologically, the most important factor that controls the distribution of organism on Earth is

Options

A. Rainfall
B. Temperature
C. Light
D. Humidity

Answer

To solve the question regarding the most important ecological factor that controls the distribution of organisms on Earth, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the ecologically most important factor that influences the distribution of organisms on Earth.

2. **Identify Factors**: Ecological factors can be categorized into two main types:
- **Biotic Factors**: These include living components such as plants, animals, and microorganisms that interact with each other.
- **Abiotic Factors**: These are non-living components such as temperature, humidity, rainfall, and pressure.

3. **Focus on Abiotic Factors**: Among the abiotic factors, we need to determine which one has the most significant impact on the distribution of organisms.

4. **Evaluate Temperature**: Temperature is a critical abiotic factor. It affects:
- Physiological processes: Temperature influences metabolic rates, enzyme activity, and overall physiological functions in organisms.
- Habitat suitability: Different organisms have specific temperature ranges in which they can survive and thrive.

5. **Conclusion**: Given that temperature plays a crucial role in regulating the physiological processes of organisms and their habitats, it is the most important ecological factor controlling the distribution of organisms on Earth.

6. **Final Answer**: The correct answer is **Temperature**.