Final answer:
UV-B rays, with wavelengths of 290-320 nm, account for 95% of solar UV radiation reaching Earth's surface. They are more prevalent than UV-A and contribute to skin cancer through indirect DNA damage.
Step-by-step explanation:
The ultraviolet (UV) light that penetrates our skin is made up of two types of radiation: UV-A rays and UV-B rays. UV-B rays, with wavelengths of 290-320 nm, account for 95% of solar UV radiation reaching Earth's surface. UV-B radiation is more prevalent than UV-A and is responsible for causing skin cancer through indirect DNA damage.