Explanation: Compositional innovations in order from the earliest to the most recent were:
1. The Guidonian hand: Musical system invented by Guido de Arezzo in the medieval ages, which consisted of reading at first sight using his own hand as a tool for learning.
2. Organum: It arose approximately in the twelfth century, and consisted of the repetition of a melody, and the addition of a new voice to the flat song.
3. Polyphony: It is the melody where multiple voices sound and probably arose from 1500 to 1575.
4. Motet: It consists mainly of biblical themes. It is believed that it emerged in the thirteenth century.
Share cropping allowed African Americans to have a sense of freedom, because basically in this system, you would take care of someone else's crops. If they had a good harvest, you get a part of the share.