Which describes how early humans used wind and solar power for the same purpose?

a. to heat their homes in the winter months
b. to pump water from a river to another location
c. to grind grain into powder that could be used for other purposes
d. to provide relief from the heat during the summer

C. to grind grain into powder that could be used for other purposes  

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.