What protects earth from ultraviolet rays?

Answer 1

The short answer is: Earth molten iron core!

This on its own is a wrong answer, but looking at the "big picture" you will see why:

The Earth is in actually protected by the magnetosphere, which is a magnetic field radiating out from the north- and south-pole of the globe.

This magnetic field deflects the deadly ray from the sun, also called Solar Wind.

Without it Earth would be as deserted and seemingly lifeless as Mars.

The magnetosphere, is more teardrop shaped, rather than round as the name suggest, with the flat side toward our Sun.

This magnetosphere is actually made in the Earth molten iron core, with the interaction between the layers the friction actually produces a magnetic field, this field stretches 70,000 km out in space toward the sun, and roughly double as long away from the sun.

Answer 2

It is not the element that protects us from UV rays but its another form. It is Ozone, the triatomic form of oxygen element.

Answer 3

The ozone layer protects us from UV rays. It is present in the stratosphere.