Final answer:
Fred Astaire made his mark in popular music through his film performances, which showcased his dancing and acting. Alan Freed popularized rock and roll as a disc jockey, while 'The Jazz Singer' was the first successful talking motion picture in 1927.
Step-by-step explanation:
Fred Astaire's contribution to popular music was not made on records or radio, but rather through the medium of film. He was known for his exceptional dancing and acting skills, which were primarily exhibited on the silver screen. Astaire's style, grace, and inventiveness in films such as 'Top Hat' and 'Swing Time' left a lasting impact on the world of dance in cinema. Moreover, his performances popularized the songs featured in his movies, contributing to the spread of popular music of the time.
The disc jockey who popularized rock and roll was Alan Freed. Freed was instrumental in bringing rock and roll to the forefront of the music scene through his radio shows, which captivated the teenage audience of the era. Likewise, the first successful talking motion picture released in 1927 was The Jazz Singer, which heralded a new age for the film industry with its use of synchronized dialogue.