What important things did Khrushchev do that changed the USSR and the world?

Krushchev started the space race by launching Sputnik I into space. In addition, he helped to resolve the Cuban Missile Crisis and create many liberal reforms in the USSR.

whose power in the senate is equal to the power of the speaker of the house?

no options provided, here,but the answer to this question is often: a historian cites a japanese newspaper article published a year after the end of world war ii in order to draw conclusions about the effect of the war on the japanese economy.

clearly from the answer, the historian alludes to historical sources,and records to aid in analyzing and drawing conclusion on the effect of the war on the economy of japan.