Final answer:
Girl groups revolutionized R&B and Rock and Roll by challenging gender norms and contributing to the genre's diversity.
Step-by-step explanation:
The girl groups revolutionized R&B and Rock and Roll by challenging gender norms and contributing to the genre's diversity. They brought a new level of sophistication to R&B and Rock and Roll, introducing complex musical arrangements. Their impact was not minimal, as these genres were shaped by both male and female artists.