Answer:
The answer is: The clef.
Explanation:
The clef in musical notation is a sign whose function is to indicate the height of written music, assigning a certain note to a line of the staff, which is taken as a reference point to establish the names of the rest of the notes. It is located at the beginning of each staff, although it can be changed at any time during the course of the work if required.
The answer is: The clef.