Answer: Composition is a way of guiding the viewer's eye towards the most important elements of your work, sometimes – in a very specific order. A good composition can help make a masterpiece even out of the dullest objects and subjects in the plainest of environments.
Explanation:
Classical Greek choruses consisted of a group of actors who delivered lines in unison. Their lines in the play were usually a commentary on the action/plot of the play, and they acted as a stand-in for the audience.
A time signature is the number of beats i each bar. eg

means a three quarter note