Which of the following type of ecosystem is expected in an area where evaporation exceeds precipitation, and mean annual rain-fall is below 100mm ?

Options

A. Grassland
B. Shruby forest
C. Desert
D. Mangrove

Answer

To determine the type of ecosystem expected in an area where evaporation exceeds precipitation and the mean annual rainfall is below 100 mm, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- **Evaporation**: This is the process by which water is converted from liquid to vapor, leading to a loss of moisture from the soil and water bodies.
- **Precipitation**: This refers to any form of water, liquid or solid, that falls from the atmosphere to the Earth's surface, including rain and snow.

2. **Analyze the Conditions**:
- The question states that evaporation exceeds precipitation. This means that the area is losing more water than it is receiving.
- The mean annual rainfall is less than 100 mm, indicating a very dry environment.

3. **Identify Ecosystem Types**:
- We need to consider ecosystems that thrive in extremely dry conditions.
- Common ecosystems include deserts, grasslands, forests, and mangroves.

4. **Evaluate Ecosystem Characteristics**:
- **Deserts**: Characterized by very low rainfall (often less than 250 mm annually), high evaporation rates, and extreme temperatures. They are adapted to survive with minimal water.
- **Grasslands**: Typically receive more rainfall than deserts and are not suitable for the conditions described.
- **Forests**: Require adequate rainfall to sustain tree growth and cannot thrive in areas with less than 100 mm of annual rainfall.
- **Mangroves**: These ecosystems are found in coastal areas and require specific conditions, including adequate water supply, which is not present in this scenario.

5. **Conclusion**:
- Given the conditions of high evaporation and low precipitation, the ecosystem that fits this description is the **desert**. Deserts are known for their arid conditions, where evaporation significantly exceeds precipitation.

### Final Answer:
The expected type of ecosystem in an area where evaporation exceeds precipitation and mean annual rainfall is below 100 mm is a **desert**.

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