What is the ozone layer?

• A. A layer protecting Earth from UV radiation
• B. A layer in the stratosphere for weather patterns
• C. A magnetosphere layer
• D. A layer of ozone in the troposphere

Answer: (A)

The ozone layer is a region in the stratosphere with a higher concentration of ozone (O3) that serves as a shield by absorbing most of the Sun’s ultraviolet radiation, especially the harmful UV-B and UV-C rays. This absorption greatly reduces the amount of UV reaching Earth’s surface, protecting living things from DNA damage, skin cancer, cataracts, and ecological harm. It’s not about weather patterns—the weather happens mainly in the lower atmosphere (the troposphere). Ground-level ozone in the troposphere is a pollutant, not the protective shield the term “ozone layer” refers to. The magnetosphere is a different part of Earth’s environment governed by magnetic fields, not chemical absorption of UV radiation. In short, the protective role and the stratospheric location make the description as a shield against UV radiation the best fit.