What the hell is this a answer
Because they create their own food so they capture sunlinght to produce sugars
Every cell of the organism has the same DNA sequence and same genes. However, not all genes are expressed in every single cell at the same time. Only those genes necessary for a specialised function of a specialised cell are expressed in the specialised cell. For example, skin cells have some different proteins than nerve cells. Genes responsible for those "skin proteins" are activated in skin cells and are turned off in nerve cells.
Fossil evidence because these changed occur over long time periods (millions of years).
