Answer: The following statement is correct:
- The United States saw the launching of Sputnik as a Soviet challenge and joined the Space Race competition.
The other statements are not accurate:
By successfully sending Sputnik into orbit, the Soviet Union won the Space Race competition with the United States. This statement is not correct because the Space Race was a competition between the United States and the Soviet Union to explore space, and it continued for many years after the launch of Sputnik in 1957.
By placing Sputnik into orbit, the Soviet Union started up the Space Race competition with the United States. This statement is not accurate because the Space Race had already begun before the launch of Sputnik, with both the United States and the Soviet Union competing to develop rockets, satellites, and other space technologies.
By launching Sputnik, the Soviet Union responded to the U.S. lead in the Space Race competition to explore space. This statement is not accurate because the United States did not have a significant lead in the Space Race at the time of Sputnik's launch. While the United States had made some progress in developing space technologies, the Soviet Union had already achieved several important milestones, including launching the first artificial satellite and sending the first human, Yuri Gagarin, into space.