Original sentence: For example, a recruit may be promoted to this rank upon entering service, if they are able to assist their recruiters in enlisting others, can pass a knowledge test and a PT test prior to leaving for Recruit Training ('Boot Camp'), have earned 48 college credits, by serving three years in a  JROTC program and are recommended by the senior instructor, or serving 1 year of Senior Reserve Officer Training Corps (College ROTC).Then there is also the United States Naval Sea Cadets Corps where if you obtain the rank of E-3 Seaman you recieve PFC for the Marines
Edited sentence: For example, a recruit may be promoted to this rank upon entering service, if they are able to assist their recruiters in enlisting others, can pass a knowledge test and a PT test prior to leaving for Recruit Training ('Boot Camp'), have earned 48 college credits, by serving three years in a JROTC program and are recommended by the senior instructor, or serving 1 year of Senior Reserve Officer Training Corps (College ROTC).Then there is also the United States Naval Sea Cadets Corps where if you obtain the rank of E-3 Seaman you receive PFC for the Marines