Final answer:
Mexican and Mexican-American people living in the territories that changed ownership struggled to provide for themselves in unfamiliar lands after being awarded land grants under the treaty.
Step-by-step explanation:
The practical effect of this treaty on Mexican and Mexican-American people living in the territories that changed ownership was that they were awarded land grants under the treaty, but they struggled to provide for themselves in unfamiliar lands. They had to face challenges such as adapting to a new environment, language barriers, and navigating unfamiliar legal systems. Therefore, option C: While they were awarded land grants under the treaty, they struggled to provide for themselves in unfamiliar lands, accurately describes the practical effect of the treaty on Mexican and Mexican-American people.
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