Answer:
to protect US trading interests abroad
to resupply US naval ships
Step-by-step explanation:
In 1890s, United States adopted isolationist policies. The policies created by the US government during this time , tend to have little to no interaction with another countries.
The Naval bases were built solely to serve US interest alone without any motive to help other countries. They're created to protect US trading ships from being attacked by pirates or non-allied military. It's also served as a pace where US naval ships can came and refill their gas tanks and food supplies for the workers in it.