The envelope of air that surrounds the earth is called

Options

A. Atmosphere
B. Lithosphere
C. Hydrosphere
D. Exosphere

Explanation

To answer the question "The envelope of air that surrounds the earth is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question is asking for the term that describes the layer of air surrounding the Earth.

2. **Identifying Related Concepts**: In the study of Earth and its layers, we encounter several terms related to different spheres of the Earth, such as:
- Exosphere: The outermost layer of the Earth's atmosphere.
- Hydrosphere: The layer of water present on Earth.
- Lithosphere: The solid outer part of the Earth, consisting of rock and minerals.

3. **Focusing on the Air Layer**: Since the question specifically mentions "the envelope of air," we need to identify which of the terms relates to air.

4. **Recalling the Correct Term**: The term that refers to the layer of air surrounding the Earth is "atmosphere." The atmosphere is a mixture of gases that is essential for life on Earth.

5. **Final Answer**: Therefore, the envelope of air that surrounds the Earth is called the **atmosphere**.