In order to improve his tennis skills teenager X plays against those who are better than him?

The soviet union beat the us to the first successful launch, with the october 4, 1957, orbiting of sputnik 1, and later beat the us to have the first human in earth orbit, yuri gagarin, on april 12, 1961. the "race" peaked with the july 20, 1969, us landing of the first humans on the moon with apollo 11

Answer is c just took the test on edgenuity

Salivary gland is mouth hormones