Red blood cells, skin cells, and nerve cells in your body all have different, specialized functions. they contain the same genes, so what genetically has caused them to look so different and have such different functions?

The fertilization happens in our body with single cell and our body is form with same set of gene but with starting with single set of fertilized egg.

Explanation:

It reached to trillions of eggs. So, it is not possible to look same. The same thing happens with red blood cells, skin cells and nerve cells. Their size is different according to their work.

In our body the structure of all cell is totally different. Each and every cell is responsible for different work. Their size is according to their suitability of their job. For example, nerve cells are long because it helps to send the signals.