@dido28: I guess your professor wanted you to think the different types of equilibrium.
http://en.wikipedia.org/wiki/List_of_types_of_equilibrium
Had you said something else - he'd have been able to set a different problem, apparently contradicting what you said. Notice, when
I answered you, I qualified my answer.
@Crazymechanic: personally, I try not to breed while I'm asleep - fortunately I find the act wakes me up ;)
A man asleep is not, technically, in equilibrium ... he is aging for example. However, he tends towards some sort of equilibrium with his environment which will be achieved after he is dead.
Probably the thermodynamic example is best here - a closed system may start out with different temperatures in different places but, over time, will settle to an equilibrium where the temperature is uniform throughout. Since the system is
closed however, it still has the same total amount of energy it started out with. The individual particles of the gas are still moving (that is what "temperature"
means). Thus: "equilibrium" does not imply that energy has been lost. Therefore, pointing out that some system has components in motion does not mean the system is not in equilibrium: the professor needs to find another counter-example.