Answer: Mainly it is the zone or layer the covers the earth most times it bouces somewhat off the earth but thanks to carbon the layer has slowly opened up this is the main factor becuase the sun is constantly shooting rays of light that would harm you but thanks to the earth's layers we dont get harmed by it.
even asteroids will sometimes survive when entering the earths atmosphere and can leave deadly disease or harm the layer
Step-by-step explanation:
Have a good day :D