The romans defeated hannibal because they
had a larger army trained in superior tactics
avoided battle, waited, and counted on the loyalty of their allies
defeated him utterly at the battle of cannae in 216 bce
recruited their army by offering equipment, money, land, and citizenship to poor people

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.