As organs and organ systems continue to develop in this embryo, the eyes will contain clear, transparent lenses. how does a single group of cells differentiate to produce both the transparent lens cells as well as all the other specialized cells in the completed organism? a) each cell selectively uses certain genes to make specific proteins not found in any other cell types. b) a cell selectively deletes certain copies of genes and the remaining genes produce proteins for a specific purpose. c) each cell has the same genetic composition so specific hormones are activated to produce cell types with specific structures and functions. d) specific genes for specific proteins migrate to cells; those migrated genes are activated to produce the proteins that determine the cell's structure and function.