If humans were exposed to ultraviolet rays and high levels of radiation, it could lead to greater chances of mutations occurring in the genes of their cells. This could then lead to the cause of what

Cancer

Explanation:

sometimes a mutation of the cells leads to cancer because the cells cant stop reproducing, so you have cells that choke each other out pretty much

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus