What part of the federal government can prevent the president of the united states from controlling the supreme court by blocking appointments

Why might the spanish government have approved of the encomienda system? a the system allowed for fair treatment of all under it, leading to a happy and prosperous colony. b the system used natives as slaves which meant the government was able to maximize their profit of exported goods. c the system allowed for mostly profitable trade within the different colonies. d the system was a great example of how to successfully run a colony, making spain a world power.