The answer is C. Rubber. Iquitos profited greatly from the boom of the rubber industry, beginning in the 1900s.
I think it is Racial background
When you're climbing a mountain, the temperature decreases (it gets colder), at least in the first layer of the atmosphere, which is called troposphere. (There are four layers in the atmosphere but there are no mountains tall enough to reach the other 3 layers) and the 3 other layer's temperature changes significantly. So in short, the temperature decreases continuously the higher you reach the mountain.
One similarity thing between the both is that they both lowered the population of Europe.
Hope this helped. Have a great day! :D
