The both were not in the 20th century
A does not make any sense to me i hope this helps
a. rose
The quality of life of the Americans has improved because of the Great Society introduced by President Lyndon B. Johnson in 1964. It aims to put an end to poverty and racial injustice. High school graduation rates also rose following the implementation of several Great Society programs.
The involvement of the United States in the Vietnam war eliminated some of its programs, but others like Medicare, Medicaid, the Older Americans Act and federal education funding, remained.
The change in the frequency of an existing gene allele
