What does this mean in music?

Negative space is particularly important and highly utilized in creating

In a paragraph of no less than 125 words, explain the single most important factor involved in advancing american classical music in the twentieth century.

Where does middle c get it’s name? a. it sits in the middle of a brass clef b. it sits in the middle of the grand staff c. if sits in the middle of the alto clef d.its sits in the middle of the treble clef