Answer:
Expansion of U.S. island territories is central to building a strong navy to defend the country.
Step-by-step explanation:
Alfred Thayer Mahan was an officer of the navy of the United States that was noted as geostrategist and educator. His ideas on naval power influenced the strategic vision of the navy around the world and helped trigger the great naval investment that took place in the years leading up to the First World War. According to Mahan, the expansion of US island territories was key to building a strong navy to defend the country.