Final answer:
Cesar Chavez was the leader who championed the Mexican American movement for better agricultural wages and treatment in California, co-founding the United Farm Workers with Dolores Huerta.
Step-by-step explanation:
The leader of the Mexican American movement in California for better wages and treatment in the agriculture industry was Cesar Chavez, alongside Dolores Huerta. They co-founded the United Farm Workers (UFW) in 1962, and through union activism, they sought to improve conditions for primarily Latino/Latina migrant farm workers.
Significant milestones in their activism include the nationwide grape boycott, which ultimately led to the first contracts with California grape producers in 1970 and the right of farm workers to unionize.
A true American hero, Cesar was a civil rights, Latino, farm worker, and labor leader; a religious and spiritual figure; a community servant and social entrepreneur; a crusader for nonviolent social change; and an environmentalist and consumer advocate.