Explanation: At the beginning the choirs were 50 members who danced and sang. In the sixth century BC, Thespis was the first real actor because he had a dialogue with the choir leader. In the 5th century BC Aeschylus proposed a second actor and reduced the chorus of 50 to 12 artists and then Sophocles added a third actor and increased the chorus of 12 to 15 artists, but reduced it to a commentary role in most of his works.
The last description makes the most sense, as to how the wording "mob" and "populace" imply them as behaving as group. Called social group psychology, many people "join the crowd" when it comes to supporting or opposing certain events, causes, or acts.