Earth is protected from UV rays by

Options

A. `N_(2)`
B. `O_(2)`
C. `O_(3)`
D. `SO_(3)`

Answer

To answer the question "Earth is protected from UV rays by," we can follow these steps:

### Step 1: Identify the Layers of the Atmosphere
The Earth has several layers in its atmosphere, including the troposphere and stratosphere. Understanding these layers is essential to identify where the protection from UV rays occurs.

**Hint:** Think about the different layers of the atmosphere and their functions.

### Step 2: Focus on the Stratosphere
Above the troposphere is the stratosphere. This layer is significant because it contains the ozone layer, which plays a crucial role in protecting the Earth.

**Hint:** Remember that the stratosphere is the layer that contains the ozone layer.

### Step 3: Understand the Ozone Layer
The ozone layer is a region within the stratosphere that is rich in ozone (O3). This layer absorbs the majority of the sun's harmful ultraviolet (UV) radiation, preventing it from reaching the Earth's surface.

**Hint:** Consider what substances can absorb UV radiation and their chemical composition.

### Step 4: Explain the Function of the Ozone Layer
The ozone layer acts as a filter or shield, blocking harmful UV rays from the sun. It is often referred to as the planet's natural sunblock because it protects living organisms from the damaging effects of UV radiation.

**Hint:** Think about how a sunblock works to protect skin from UV rays.

### Step 5: Conclusion
Thus, the Earth is protected from UV rays primarily by the ozone layer, which is composed of ozone (O3). This layer is essential for maintaining life on Earth by filtering out harmful radiation.

**Hint:** Remember the chemical formula for ozone when identifying the correct answer.

### Final Answer
Earth is protected from UV rays by the ozone layer (O3) in the stratosphere.