If the atmosphere did not contain an ozone layer, which of the following could happen?

The earth would become very cold. The earth would have no weather. The earth would not be protected from sun. The earth would not be protected from meteorites. 

I learned this last year in 9th grade

They are both unlikely.  certain would be 100%, likely would be anywhere above 50%, and unlikely would be under 50%can i have brainliest, ?