What conditions prompted changes on the soviet union

 The correct answer is : The conditions that caused changes in the Soviet union were: food shortages and excessive military spending.

Explanation:  Getting food was a growing problem for a large part of the people in the Soviet Union. It was quite difficult to get chicken, fish, meat, fruits, milk, among others. This shortage was very strong in small cities. In addition to this situation, military spending was too high during the Cold War.

c, they united with once