Stem cells are cells that can differentiate into many different kinds of cells. scientists have discovered that the environment supporting the cells influences stem-cell differentiation. for example, stem cells grown on strong, flexible surfaces became muscle cells. what most likely happened to stem cells grown on a hard, rigid surface? they became nerve cells. they became skin cells. they became red blood cells. they became bone cells.

When stem cells grown on hard, rigid surface, then they became bone cells. Researchers demonstrate in Nature materials that human mesenchymal stem cells grown on a rigid substrate for some time become biased toward differentiating into bone-cell lineage, whereas cell grown on softer surfaces are just likely to eventually follow a bone or fat cell fate.

i thinking chemical change

not sure if this is what you'r looking for eubacteria and archaebacteria