# Phanerozoic Earth History

## Key Questions

• Ozone is formed by the reaction of a oxygen molecule with a oxygen atom due to high UV radiation
$3 {O}_{2} r i g h t \le f t h a r p \infty n s 2 {O}_{3}$
process is as
${O}_{2} \to 2 O$(1)due to the energy of $U V$rays
$2 {O}_{2} + 2 O r i g h t \le f t h a r p \infty n s 2 {O}_{3}$(2)
(1)-(2)
$3 {O}_{2} r i g h t \le f t h a r p \infty n s 2 {O}_{3}$
It is imprtant for the life at higher altitudes as the it absorbs the UV rays and dont allow them to fall on earth
at lower altitudes ozone is a harmful gas to the life on earth