Biochemistry Excessive ultraviolet (uv) radiation is harmful to life. The damage caused to the biological systems by ultraviolet radiation I by: A Inhibition of DNA synthesis B Formation of thymidine dimmers C Ionization D DNA fragmentation 💡 Explanation Excessive ultraviolet (uv) radiation is harmful to life. The damage caused to the biological systems by ultraviolet radiation I by: ✓ Correct Answer: B. Formation of thymidine dimmers