The correct answer here is the third option.
The "domino effect" is a term used a lot over the course of the Civil War and it was explained by this quote by president Dwight D. Eisenhower and it refers to the communist situation in Indochina. He talked if the states fall there, communism will spread further. This lead to the US support of non-communist government of South Vietnam.
Martin Luther King Jr. advocated for nonviolent (peaceful) protests in order to gain civil rights for African-Americans. Malcolm X was similar in the sense that he wanted equal rights, however he was in favor of using violence in order to do this.
Another important Civil Rights leader was Rosa Parks. She refused to give up her seat to a white passenger in a "white only" section of a Montgomery Bus. This resulted in the Montgomery Bus Boycott, which helped end segregation on buses in Alabama.
John F. Kennedy was the man assassinated on November 1963. His assassin was Lee Harvey Oswald. Only one day after Kennedy was killed, Oswald was killed by a Dallas night club owner by the name of Jack Ruby. Even though Kennedy died, his legacy lived on when Lyndon B. Johnson was able to get the Civil Rights Act of 1964 passed. This was a document Kennedy worked on for a long time, unfortunately he was killed before it could pass in Congress.
Answer: The space race was considered an important part of the cold war and it showed the world which country has the best science technology and economic system
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