The cyanobacteria changed the composition of the earth’s atmosphere by evolving oxygen in what is referred to as the Great Oxygenation Event. This also allowed the ozone to be formed and block off most of the UV rays that are destructive to genetic material. Life was, therefore, also able to exist on land other than in water.
A. in DNA can result in dysfunctional protein productiona. Your answer is Point mutation
B. defiantly b. because it can survive in most climates.
The subunits are called nucleotides
