Answer the following question given this paragraph: 

Between 1971 and 1982, the Soviets put a total of seven Salyut space stations into orbit. Figure below shows the last of these, Salyut 7. These were all temporary stations. They were launched and later inhabited by a human crew. Three of the Salyut stations were used for secret military purposes. The others were used to study the problems of living in space. Cosmonauts aboard the stations performed a variety of experiments in astronomy, biology, and Earth science. Salyut 6 and Salyut 7 each had two docking ports. One crew could dock a spacecraft to one end. A replacement crew could dock to the other end.


Q: What country put seven salyut space stations into orbit between 1971 and 1982?

 Choices:

- United States

- China

- Japan

- soviet union

A:
soviet union
