Physical structures..........
Answer:
exposure to ultraviolet radiation is a correct answer.
Explanation:
Ultraviolet light exposure results in the formation of pyrimidine dimers. Ultraviolet radiation damage the DNA by resulting in chemical changes.
Ultraviolet radiation is absorbed by the pyrimidine bases( cytosine and thymine in DNA) and result in the formation of covalent bonds between the succeeding bases.
The formation of the pyrimidine dimers results in the distortions of DNA helix and disrupt the base-pairing during the replication of DNA which results in a mutation.
B press a clean towel or cloth firmly against the cut. you don't want the bleeding to continue and don't want to make the cut worse by putting any liquid in a lab, like acid that could easily be mistaken as water.
Pines, spruces, and firs are conifers