Final answer:
The control of American popular music after the first wave of rock and roll ended was taken over by Pop artists, with influence from figures like Elvis Presley and Bill Haley.
Step-by-step explanation:
As the first wave of rock and roll began to wane, control of American popular music was predominantly taken over by Pop artists. During this time, pop music was heavily influenced by the rock and roll genre, but began to differentiate itself by focusing more on melodious tunes and romantic lyrics, appealing to a broad audience. Figures like Elvis Presley and Bill Haley, who had been pioneers in the rock and roll movement, helped to bridge this transition, as they continued their success into this new era of music. They, along with other artists, incorporated elements of the earlier rock and roll into their music, thus paving the way for Pop artists to rise.
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