<prompt> Uv radiation has which of the following effects on cellPrevents formation of pyrimidine dimersStimulates formation of pyrimidine dimersPrevents formation of purine dimersAll the above  <response>: Ref Robbins 8e p312, 9e p314 The carcinogenicity of UV_B light is attributed to its formation of pyrimidine dimmers in DNA.this type of DNA amage is repaired by the nucleotide extension repair pathway of DNA repair is illustrated by hight frequency of cancers in individuals with the hereditary disorder xeroderma pigmentosum 