Which radioisotope is naturally occurring?

 94238pu

 13h

 96242cm

 103258lr

I think the answer is 13H

Explanation:

The best known example of a naturally-occurring radioisotope is uranium. All but 0.7 per cent of naturally-occurring uranium is uranium-238; the rest is the less stable, or more radioactive, uranium-235, which has three fewer neutrons in its nucleus.

the role of the microscope world in creating new materials .