In normal body-cell reproduction (called mitosis) the chromosomes, which are generally paired (Fig. 1) duplicate themselves (Fig. 2).  Then the cell divides into two daughter-cells, each with the same number of chromosomes as the Mother cell (Fig. 3).

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Figure 1.

Mother cell showing nucleus with paired chromosomes prior to the onset of the duplicating process.

 
 

Figure 2.

Mother cell showing nucleus with "duplicated" chromosomes preparing to divide.

 
Figure 3.

Mother cell shown dividing with a full compliment of paired chromosomes migrating to the eventual daughter cells.  The resulting daughter cells - each having a full compliment of paired chromosomes - are copies of the original Mother cell.  At the onset of the process there was one cell; now there are two