Dismantled Beetle, 2003 by Damian Ortega, Venice Biennale.
Answering the question posed above, is a big job. I believe that it cannot be answered definitively and must be left up up to the individual.
Let me tell you about a personal experience of mine that related to this subject. I was in graduate school working on my masters degree in art history and working at my father's law office. He had occasion to need a definition of art, as a citizen of the town he represented, had taken it upon himself to hoist an old VW bug up on a stump in his yard. When asked to remove it by the local government, the citizen refused saying it was art and he had a right to display it. This caused my father to have to take the man to court to try and compel him to remove the car from the stump. The city was claiming it was not only and eyesore, but a danger.
My father's thought he could get his art historically educated daughter to define art for him, and surely this old car on a stump would not fall within that definition. Well, I told him I could not give him one definitive definition of what art was and that I was sorry, but in some people's eyes, a VW was art. He does not often become angry with me, but this time he did. I wanted to be able to solve his problem, but I knew I could not, as I feel it is an individual interpretation when it comes deciding what is and is not art.
In the end, it turned out the stump was on someone else's property and it was removed, but the question of whether or not it was art, is still not resolved.