I believe the answer is "b", sorry if i am incorrect.
It can cause forced labor in many parts of the world
Although America fought in many wars since, World War 2 was the last time the nation declared war (actually against two nations at the time). One declaration of war with Japan, and one declaration of war with Germany. I hope this helped !!
Answer:
Given the information that we have here, we are told that the Mayans were isolated due to the mountain ranges and surrounding natural barriers. This didn't allow for good trade routes for other civilizations. Due to such isolated conditions and harsh traveling environment, any other nearby civilizations would have not wanted to risk such perils for trade. The Mayans did in fact have natural resources, as we are told here that they used stone, bone, and wood in order to aid in the construction of their cities.