"Don't buy where you can't work" was the protest slogan of

“The "Don't Buy Where You Can't Work" movement, also known as the "Buy Where You Can Work" movement, emerged in major northern U.S. cities during the Great Depression to protest black unemployment rates that often were double or triple the national average.“

Explanation:

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peace keepers

idealism to be spread

riches kept

the correct answer is:   the domino theory states that if one country in a region came under the influence of communism, then the surrounding countries would follow in a domino effect.