Which layer of the atmosphere protects you from ultraviolet (UV) light?

• A. Exosphere
• B. Mesosphere
• C. Troposphere
• D. Ozone layer

Answer: (D)

Verified step by step guidance

1. Understand the role of the ozone layer in the atmosphere: The ozone layer is a region within the stratosphere that absorbs and blocks most of the Sun's harmful ultraviolet (UV) radiation, protecting living organisms on Earth.
2. Identify the location of the ozone layer: The ozone layer is specifically found in the stratosphere, which is the second layer of Earth's atmosphere above the troposphere.
3. Clarify why the other layers listed in the problem do not protect against UV light: The exosphere is the outermost layer and does not contain significant ozone. The mesosphere is above the stratosphere but lacks the ozone concentration needed to block UV light. The troposphere is the lowest layer where weather occurs, but it does not have the ozone layer.
4. Relate the ozone layer's function to its chemical composition: Ozone (O₃) molecules absorb UV radiation, particularly UV-B and UV-C, preventing these harmful rays from reaching Earth's surface.
5. Conclude that the correct answer is the ozone layer, which is located in the stratosphere and serves as Earth's primary defense against UV radiation.