As a junior high school teacher, melanie lectures on the dangers of cigarette smoking, yet before and after school each day she smokes several cigarettes. Melanie violates the ethical standard of

teaching

Explanation:

Teaching means practising what it is being taught as it is the thing to do. Teaching that smoking is bad and then smoking means this teacher is violating the very purpose of teaching. What is taught is right, what is right is to be done and this person is acting the other way around, doing what she is transmitting the kids not to do because it is dangeous and really bad for one's health.

Melanie is being a hypocrite, teaching not to do the very thing that she herself does every day!