Question

the spanish who lived and worked in missions often forced native americans to
a gather food and water for them.
b fight other colonists for them.
c change their languages, religion, and customs.
d moved farther into the forest areas of the state.

Explanation:

The Spanish in missions aimed at cultural assimilation. Forcing language, religion, and custom changes was a key part of their efforts to convert and control Native Americans. Gathering food/water (A) was a task but not the main forced cultural aspect. Fighting other colonists (B) wasn't a common forced activity on Native Americans by mission - based Spanish. Moving into forests (D) was more of a Native American response to avoid such forced changes rather than a forced action by the Spanish.

Answer:

C. change their languages, religion, and customs.