Widely read by Americans of the Founding generation, Polybius stressed that historical changes in political forms occurred

u.s.a

china

india

and

japan

because the vietnam war was fought in an especially brutal and untraditional way

the correct answer option is: weapons.

explanation:

tensions rose as the two opposing superpowers competed for 'weapons'.

referring to the cold war (1945-1991), the two superpowers, usa and ussr, experienced a phase of struggle and conflict with each other. these two superpowers considered each other as a threat to their survival and thus opted for policies to strengthen their positions.

the two superpowers never went to war with each other directly but competed for weapons to preserve their positions.