Short answers, pulled from the story.
Rock music is a genre of popular music that originated in the United States as rock and roll in the late 1940s and early 1950s. It developed into a range of styles from the late 1950s to the mid-1960s, primarily in the United States and United Kingdom. It drew from blues, rhythm and blues, gospel, and country music, centered on the electric guitar.
In 1951, Cleveland, Ohio disc jockey Alan Freed is credited with first using the phrase rock and roll to describe the music. He began playing rhythm and blues, then termed race music, for a multi-racial audience.
Bill Haley's "Rock Around the Clock" became the first rock and roll song to top Billboard magazine's main sales and airplay charts in 1954. It opened the door worldwide for the new wave of popular culture.
The Beatles led the British Invasion and advanced the album ahead of the single as the dominant form of recorded music. Their first appearance on The Ed Sullivan Show on the 9th of February 1964 drew an estimated 73 million viewers, and during the week of the 4th of April 1964 they held the entire top five of the Billboard Hot 100. They became the biggest selling rock band of all time.
Punk rock was developed between 1974 and 1976 in the United States and the United Kingdom. By late 1976 the Ramones and Patti Smith in New York City, and the Sex Pistols and the Clash in London, were recognized as the vanguard of the movement.
Grunge formed in Washington state, particularly around Seattle, in the latter half of the 1980s, using heavy guitar distortion, fuzz, and feedback with apathetic, angst-filled lyrics. It remained largely local until 1991, when Nirvana's album Nevermind became a huge success with the song "Smells Like Teen Spirit."
Rock was the most popular genre in the U.S. and much of the western world from the 1960s up to the 2010s, but since the 2010s it has lost its position as the pre-eminent popular music genre in world culture. The increased influence of hip-hop and electronic dance music can be seen in rock, though it remains commercially successful.