To help support agriculture in Mesoamerica, a system was created.

im not entirely sure, but it i think it was the slash and burn.  (it might not be a system though)

Explanation:

..

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.

the answer is c. to explore the louisiana purchase