Knowing how to easily manipulate the people around you. Not exactly a good thing though.
The reason why ethics differs when we're talking about people, companies, nations is that all of these have interests which may differ. What happens then with differing interests is that it also lead to different moral and value systems which again in turn lead to different ethics. Most usually, the actual source why ethics differ is either due to the interests or wishes of a particular social group mentioned here.
Answer:
A.messages that are sent from the brain to body parts
