What 3 things are important in determining whether something is 'art' ?

Maybe Art as Representation  

Art as Expression of Emotional Content and  

Art as Form

Explanation:

I'm not sure because it's kind of subjective to opinion, but these are three categories for the definition of art

including the octave, the answer would 8 notes in a major scale with one note being played twice. ex) c major scale includes: c, d, e, f, g, a, b, c

notice that c is played twice

however, if you were to ask me how many different notes are in a major scale- the answer would be 7.  

answeras live actors preforming in the same room as a live audience;