Short answers, pulled from the story.
Rock music originated in the United States during the late 1940s and early 1950s. Cleveland disc jockey Alan Freed is credited with first using the phrase rock and roll to describe this new sound.
Sister Rosetta Tharpe's Strange Things Happening Every Day from 1944 is a contender for the title of the first rock and roll record. Arthur Crudup's That's All Right from 1946 is another contender that Elvis Presley later covered in 1954.
The Beatles held twelve positions on the Billboard Hot 100 singles chart during the week of the 4th of April 1964 including the entire top five. This event helped internationalize production of rock and roll while denting careers of established R&B acts like Fats Domino and Chubby Checker.
Steppenwolf Born to Be Wild from 1967 first used the term heavy metal in music. The Rolling Stones and Black Sabbath further developed characteristic sounds shaping the subgenre by 1970.
Garage rock style peaked commercially and artistically around 1966 before largely disappearing from national charts by 1968. New styles evolved to replace garage rock as regional variations flourished across California and Texas.