Final answer:
Base analogs, such as 5-bromouracil, can cause mutations by chemically altering nitrogenous bases in nonreplicating DNA. Hence the correct answer is option A
Step-by-step explanation:
Base analogs, such as 5-bromouracil, can cause mutations by chemically altering nitrogenous bases in nonreplicating DNA. This is true. Base analogs are structurally similar to normal nucleotide bases and can be incorporated into DNA during replication. However, they often have different base-pairing rules than the bases they replace, leading to mutations. Other chemical mutagens can modify existing bases, resulting in different base-pairing rules as well.