Ozone, a molecule made up of three oxygen atoms (O3), forms a layer in the stratosphere, about 10 to 50 kilometers above the Earth's surface. This layer acts as a shield, absorbing most of the harmful UV radiation from the sun, preventing it from reaching the Earth's surface.
Without this ozone layer, life on Earth as we know it would be impossible, as UV radiation can cause severe damage to living organisms, including skin cancer, cataracts, and damage to plants.