Temperature decreases progressively from the

Options

A. equator towards the poles
B. poles towards the equator
C. plain towards mountain
D. both 1 and 3

Answer

### Step-by-Step Solution

1. **Understanding Temperature Variation**: Recognize that temperature is a critical abiotic factor in ecosystems. It influences the distribution and behavior of organisms.

2. **Temperature Gradient from Equator to Poles**: Note that temperature decreases as one moves from the equator towards the poles. This is due to the angle of sunlight and the amount of solar energy received in different regions.

3. **Temperature Variation with Altitude**: Understand that temperature also decreases with an increase in altitude. As you move from plains to mountains, the air becomes thinner and cooler.

4. **Temperature Extremes**: Acknowledge the extremes of temperature that can occur in different environments, such as sub-zero temperatures in polar regions and over 50 degrees Celsius in tropical deserts during summer.

5. **Ecological Relevance of Temperature**: Recognize that temperature affects biological processes such as enzyme activity, metabolism, and overall physiological functions of organisms. This makes it a significant factor in ecological studies.

6. **Conclusion**: Based on the understanding of temperature gradients, conclude that temperature decreases both from the equator towards the poles and from plains towards mountains.

### Final Answer
The correct statement is that temperature decreases progressively from the equator towards the poles and from plains towards mountains.