Air : Atmosphere : : Water : ?

Options

A. Hydro-sphere
B. Eco-sphere
C. Prio-sphere
D. Strato-sphere

Explanation

To solve the analogy question "Air : Atmosphere :: Water : ?", we need to analyze the relationship between the first pair of words and apply the same logic to the second pair.

### Step-by-Step Solution:

1. **Identify the Relationship**:
- The first pair is "Air : Atmosphere". Here, air is a component that makes up the atmosphere.

2. **Find the Corresponding Component for Water**:
- Now we need to find what water constitutes, similar to how air constitutes the atmosphere.

3. **Understand the Term for Water**:
- Water is a fundamental part of the hydrosphere. The hydrosphere includes all the water on Earth, including oceans, rivers, lakes, and even water vapor in the atmosphere.

4. **Formulate the Answer**:
- Since water constitutes the hydrosphere, we can conclude that the answer to the analogy is "Hydrosphere".

5. **Final Answer**:
- Therefore, the answer to the analogy "Air : Atmosphere :: Water : ?" is "Hydrosphere".