Mutations are rare and occur because of?
-an error in dna replication
-natural event such as an earthquake
-migration of organisms to a new population

thymine. in rna, thymine is replace by uracil

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.