Answer: c) rhythm
Explanation:
Rhythm (to flow) is the positioning of sounds in time.
It is the one indispensable element in music. It is a measured motion (I.e a pattern) of strong and weak elements (contrasting elements) in the flow of sound (music).
i would suggest whatever you would like as a good app
Answer: So he knows how they respond to certain things, and knows how to better portray the message he's trying to send.