Old enough to fight, old enough to vote” became a major rallying cry for which amendment to the Constitution

That would be the 26th Amendment. "The right of citizens of the United States, who are eighteen years of age or older, to vote shall not be denied or abriged by the United Statea or by any State on account on age." (rewritten in simpler terms)

what the first or next guys says

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.