Deserts receive rainfall of less than 25 cm annually. How much area
of land is desert?

Options

A. About 10 to 15%
B. About 33%
C. About 15 to 20%
D. About 40%

Answer

To determine how much area of land is classified as desert, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Deserts**: Deserts are regions that receive less than 25 cm of rainfall annually. This low precipitation leads to arid conditions where only specific types of flora and fauna can survive.

2. **Identify the Global Coverage of Deserts**: Deserts are found on every continent and cover a significant portion of the Earth's land surface.

3. **Calculate the Percentage of Desert Area**: It is known that deserts cover about one-fifth of the Earth's land area. To convert this fraction into a percentage:
- One-fifth can be expressed as 1/5.
- To convert to a percentage, multiply by 100:
\[ \frac{1}{5} \times 100 = 20\% \]

4. **Select the Closest Answer**: The options provided in the question are:
- About 10-15%
- About 33%
- About 15-20%
- About 40%

Since we calculated that deserts cover about 20% of the land area, the closest option is "about 15-20%."

5. **Conclude the Answer**: Therefore, the area of land that is classified as desert is approximately 15-20%.

### Final Answer:
The area of land that is desert is about 15-20%.