Learned from there mistakes and try to not repeat the same mistakes they've made
<span>A and D, or the fear of nuclear attack and increased study of science and math are the effects of the arms race. The nuclear arms race was an opposition between the United States and the Soviet Union for atomic weapons prevalence enduring all through the Cold War.</span>
Explanation:
Feudalism was a social and political system. ... Under feudalism, the king owned all of the land in his kingdom. However, the king would give gifts of land (called fiefs) to the lords or nobles who fought for him. These people were called “vassals.” Vassals would allow peasants called serfs to live on parts of their land.At the very top of feudal society were the monarchs, or kings and queens. As you have learned, medieval monarchs were also feudal lords. They were expected to keep order and to provide protection for their vassals. ... They had to rely on their vassals, especially nobles, to provide enough knights and soldiers.