The ozone layer to sustain terrestrial life by

Ozone is a layer of gas in the atmosphere that is represented by O₃. It has an essential role in sustaining life forms on earth. It prevents the harmful ultraviolet rays ( that come from sun) to reach the earth. These radiations are absorbed by ozone layer and therefore it acts like a protective shielding layer for the planet earth.

i might be wrong but i think its a. let me know if i’m right and have a good rest of your day!

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.