Answer:
- Measured rhythm, and syncopation.
Explanation:
As per the question, the given two blanks could be filled up by the words 'measured rhythm and syncopation' as these technical changes would help to have a significant impact on music notation. The 'measured rhythm' implies the placement of beats or sounds within a specified time would help produce the intended accent and pattern of the music while syncopation implies 'a temporary displacement of a regular(metrical) accent in order to lay stress on a weak beat' that would help produce distinct sounds leading to create a significant impact. Thus, 'measured rhythm and syncopation' is the answer.