| − | Special structures or chemicals that allow living [[organism]]s to sense the conditions of their surroundings.<ref>Wile, Dr. Jay L. ''Exploring Creation With General Science''. Anderson: Apologia Educational Ministries, Inc.
| + | '''Receptors''' are special structures or [[chemical]]s that allow living [[organism]]s to sense the conditions of their surroundings.<ref>Wile, Dr. Jay L. ''Exploring Creation With General Science''. Anderson: Apologia Educational Ministries, Inc. |