Answer:
Your three blood cell types have different sizes, shapes, and functions. Yet they all started out alike. Within each cell of your body there are chromosomes which give the instructions for cell processes. These instructions include the differentiation of your blood cells
Step-by-step explanation:
In the chromosomes the DNA is packed, from its sequence and from other control mechanisms the genetic expression is regulated and instructions are given to generate one or another type of cell. This happens because there is a differential expression of the different genes according to the cell type.