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1.Sputnik 1 remained in orbit
a) for nearly six months
b) for nearly seven months
c) for twenty-one days
2.While it was in orbit, Sputnik 1
a) transmitted a radio signal
b) raced with US satellites
c) conquested all of space
3.All satellites, both natural and artificial,
a) have been launched
b) have transmitted
c) are in orbit
