The disc jockey who popularized rock and roll was

bill haley
elvis presley
alan freed
ed sullivan

Definitely was Mr. Alan Freed.

Explanation:

Mr. Alan Freed was considerate as one of the most important popularized the Rock and Roll during the 50s.

From popularizing the R&B records that did become the foundation of rock to planning the first rock and roll concert, he was the tireless promoter of the genre.

affirmative action refers to the policies that take gender, race, or ethnicity into account in order to promote equal opportunity.

employers subject to title vii are prohibited from taking race or sex into account in any employment decisions. aa is a penalty for having any job group substantially statistically "underutilized" in any race or either sex. the employer must take steps to eliminate the underutilization, then stop, ending its aa efforts

during both period congress passed law restricting the civil liberties of american citizen that meet with the overall public support is the one statement that explain the rate scare of the 1920 and 1950 is very similar