Europeans carried a hidden enemy to the Indians: new diseases. Native peoples of America had no immunity to the diseases that European explorers and colonists brought with them. Diseases such as smallpox, influenza, measles, and even chicken pox proved deadly to American Indians.
The best example of "gunboat diplomacy" under Roosevelt is "<span>C. Panama" since Roosevelt felt that this region was also a part of the US's interest since it was open to attack. This was also his "big stick diplomacy".</span>