Complex sentence: During the 1970's the phrase was common amongst teens and young adults marking the dividing line between the social class of marijuana users and those who did not, with the color red referring to the non-users as rednecks.
Split into simpler sentences: During the 1970's the phrase was common amongst teens and young adults marking the dividing line between the social class of marijuana users and those who did not. With the color red referring to the non-users as rednecks.