Here is the correct arrangement of terms to fill in the blanks:
Mitosis produces two daughter cells that are genetically identical to the parent cell. However, before a cell divides, the cell must first replicate (copy) its chromosomes. The cell then splits the replicated chromosomes equally, so each new daughter cell has its own full set of identical chromosomes.
So the filled-in passage would read:
Mitosis produces two daughter cells that are genetically identical to the parent cell. However, before a cell divides, the cell must first replicate (copy) its chromosomes. The cell then splits the replicated chromosomes equally, so each new daughter cell has its own full set of identical chromosomes.