The correct answer is option 2: Ozone. Ultraviolet (UV) radiation from the sun is divided into three types: UVA, UVB, and UVC. UVC rays are the most dangerous type, but they are fully absorbed by the Earth`s atmosphere and do not reach the surface. UVA and UVB rays can both reach the Earth`s surface and cause damage to our skin and eyes. However, in the stratosphere, there is a layer of ozone (O3) that acts as a shield and absorbs most of the UVB radiation. This absorption process converts the UVB rays into heat energy, protecting us from its harmful effects. Therefore, ozone plays a crucial role in preventing excessive UV radiation from reaching the Earth`s surface and harming living organisms.