As the embryo's cells divide, the genetic material within them, called &quot;DNA&quot; , instructs certain cells to &quot;specialize&quot;-- that is become heart cells, lung cells, bone cells, brain cells, etc.
(the embryo's cells; divide; ) (the genetic material within them; called; ) (that; is become; heart cells, lung cells, bone cells, brain cells, etc.)
the embryo's cells the genetic material within them that
divide called is become
heart cells, lung cells, bone cells, brain cells, etc.