And in an analogous way, at the early stages of life, at the early stages those cells are totipotent. They can become any cell whatsoever. But as the process of development continues, eventually cell determination takes place. They choose their majors and eventually they undergo these set of processes called cell differentiation that allows them to become that nerve cell. So cell differentiation, for example, is analogous to a person choosing the pre medical path and then following a certain set of processes taking the prerequisite courses, taking the MCAT, volunteering, applying to medical school, going to medical school, and so forth. And these processes eventually allow that person to differentiate into that physician.