What important factor does the ozone layer serve in earth's atmosphere?

The Ozone layer is responsible for the absorption of harmful radiation from the sun before it hits the surface or exterior structure of our planet. It is known to be a belt of a known occurring gas, known as “ozone” which is sealed around the Earth’s atmosphere. It serves as a shield, which absorbs most of the sun’s ultraviolet radiation. 

i would say

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2