C. As a country gains colonies, its military grows to protect them.
Explanation:
The British would grow their armies every time they had colonized a nation. They would also integrate citizens of that colony into the British Army to protect British interest there.
As a country gains colonies, its military grows to protect them
Explanation:
Whenever a nation gains a colony, a nation must ensure that it has a sufficient amount of troops to protect it and ensure its under the nation's control, which would mean the nation would need to recruit more troops to provide this protection (military growth).
The United States was willing to pay more per mile for the Gadsden Purchase than for the Mexican Cession because the Gadsden Purchase gave money to the United States to build a railroad.
