I don’t think i can answer this question unless you include a picture of the line of music these questions are on. i hope this helps!!
Answer:
Attach the image,
I'll edit this post and answer your question.
Answer: Cowell
Explanation:
The first one who experimented with piano strings and clusters is Henry Cowell.
He was the first one who asked the pianist to manipulate string and then when he discovered the sound.
Before that new sound, he discovered also <u>tone clusters</u>. Tone clusters were achieved by hitting the piano keys with elbows or fists.
The little dot next to the quarter note counts as a third beat. So it basically is an extra one quarter note... I hope this helps ;)