A seems most likely, check with others if u have the time
People used vaccines to reduce the risk of infection by working with body as defenses to help them so this vaccines develop immunity to disease
I hope that's help:0
Answer:
When helicase mutations occur, problems in DNA replication are found. The helicases are proteins that open the 2 strands of DNA to initiate the duplication, they are responsible for breaking the hydrogen bonds between the two DNA chains, thus separating the chains, also they have the function of repairing DNA mutations, if there is mutation in the gene that encodes them, various functions will be absent in the cell.
you didn't list choice but i'm guessing chloroplasts