Final answer:
UV radiation causes DNA lesions in the form of pyrimidine dimerisation, leading to the potentially mutagenic formation of thymine dimers.
Step-by-step explanation:
The kind of DNA lesion that UV energy causes is pyrimidine dimerisation. Ultraviolet (UV) radiation can induce adjacent pyrimidines on a DNA strand to dimerize, particularly thymines but sometimes cytosines as well. This leads to the formation of covalent links between two adjacent pyrimidine nucleotide bases, commonly known as thymine dimers. If these dimers are not repaired, they can lead to disruptions during DNA replication and transcription, potentially resulting in frameshift or point mutations.