4. What challenges to their power did

the Spanish face?

social and political challenges

Explanation:

The Spanish faced social and political challenges due to the implementation of the Encomienda system of rule in the American colonies under the control of the Spanish crown.

The Encomendia system required that Natives of the various colonies were to be assigned to an Encomendero who will use the natives as labor in exchange for protection. The social challenges they faced were the protests gotten by Spanish priests who were against the Encomienda system because they saw it as slavery.

the political challenges they faced were the protests embarked on by Native Americans rejecting the Spanish rule in their domain

this would be Encomienda system