_____ protects the earth from harmful UV (Ultra-Violet) Radiation from sun.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → O3
Ozone (O3), a molecule of three oxygen atoms, forms a layer in the stratosphere, about 15–35 km above the Earth. It absorbs most of the harmful ultraviolet (UV-B and UV-C) radiation of the sun, which can cause skin cancer and eye damage and harm plants and animals.
The other gases in the options do not shield the Earth in this way: oxygen (O2) is the gas we breathe, carbon dioxide (CO2) is a greenhouse gas, and sulphur dioxide (SO2) is an air pollutant.