Correct Response: A. Mitosis is a process used by eukaryotic cells to generate new cells. It involves disassembling the nucleus in the parent cell and reassembling a new nucleus in each daughter cell. Prokaryotic cells (bacteria) do not contain a nucleus and use an alternate method for reproduction called binary fission. A spindle (B) is a structure used during mitosis to separate sister chromatids to opposite sides of the dividing cell. Unrepaired mutations during DNA replication can generate some genetic variability (C), but these mutations can occur in both mitosis and binary fission. Both mitosis and binary fission typically result in identical daughter cells (D), so this is not a difference between the two processes.