It's pronounced "ensemble" by the way. And, one way that a pianist would have a role would be by being in the background as an example and playing his part. He's going to play what he needs to play. The question does seem a little to vague, but truly, I would say simply, that the person who is playing it, just plays his part as they all make music sound good.
Answer: During the 1750-1820's a new musical system was developed. This was classical music.
Explanation:
Re would be the answer I’m 99%
