Final answer:
Title VII of the Civil Rights Act of 1964 prohibits race-based discrimination in employment practices.
Step-by-step explanation:
Refusing to cooperate with other brokers because of race is prohibited by Title VII of the Civil Rights Act of 1964. This act makes it unlawful for an employer to discriminate against any individual based on race, color, religion, sex, or national origin. The act applies to employment practices, including hiring, firing, pay, job assignments, promotions, and more.