The tropics have more diversity of vascular plants as compared to the temperature regions because of

Options

A. latitudinal gradient
B. longitudinal gradient.
C. temperature gradient.
D. altitudinal gradient.

Answer

### Step-by-Step Solution:

1. **Understanding the Regions**:
- The Earth is divided into different climatic regions based on latitude. The tropics are located near the equator, while temperate regions are found further away from the equator.

2. **Sunlight and Temperature**:
- The tropics receive more direct sunlight throughout the year compared to temperate regions. This is because the sun's rays strike the tropics at a more perpendicular angle, leading to higher temperatures.

3. **Impact of Temperature on Plant Diversity**:
- Warmer temperatures in the tropics create a more favorable environment for plant growth. Higher temperatures generally support a greater diversity of plant species, as they can thrive in a variety of ecological niches.

4. **Latitudinal Gradient**:
- The concept of latitudinal gradient refers to the increase in biodiversity as one moves from the poles towards the equator. In the tropics, the latitude is around 23.5 degrees north (Tropic of Cancer) and 23.5 degrees south (Tropic of Capricorn), which is optimal for plant diversity.

5. **Conclusion**:
- The combination of consistent sunlight, warm temperatures, and suitable ecological conditions in the tropics leads to a higher diversity of vascular plants compared to temperate regions. Therefore, the primary reason for this increased diversity is the latitudinal gradient.

### Final Answer:
The tropics have more diversity of vascular plants as compared to the temperate regions primarily due to the **latitudinal gradient**, which provides optimal sunlight and temperature conditions for plant growth.

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