Species diversity______as one moves from high to low altitudes.
(a) increase
(b) decreases
(c) first increases then decreases
(d) first decreases then increases

Options

A. increase
B. decreases
C. first increases then decreases
D. first decreases then increases

Explanation

To solve the question regarding species diversity as one moves from high to low altitudes, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Species Diversity**:
- Species diversity refers to the variety and abundance of different species in a particular area. It includes both species richness (the number of different species) and species evenness (how evenly individuals are distributed among those species).

2. **Consider the Impact of Altitude on Biodiversity**:
- Biodiversity is influenced by various environmental factors, including altitude. As altitude changes, the climatic conditions also change, which can affect the types and numbers of species that can thrive in those conditions.

3. **Analyze the Relationship Between Altitude and Species Diversity**:
- Generally, as one moves from high altitudes (like mountains) to lower altitudes (like plains), the climate becomes warmer and more stable. This stability and warmth can support a greater variety of species.

4. **Identify the Trend**:
- It is observed that species diversity tends to increase as one moves from high altitudes to lower altitudes. This is due to more favorable conditions for a wider range of species at lower altitudes.

5. **Select the Correct Option**:
- Based on the analysis, the correct answer to the question "Species diversity______as one moves from high to low altitudes" is:
- (a) increases.

### Final Answer:
**(a) increases**

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