The arms race between the United States and the Soviet Union began when the US first launched a nuclear missile.
the Soviet Union developed its own atomic bomb.
the Soviet Union launched its first satellite.
NASA created the Mercury program.

when the soviet union launched its satellite

Explanation:

the space race was started when the sputnik was launched into earths orbit

The Soviet Union developed its own atomic bomb.

Explanation:

Among the world leaders, the United States was the first to develop and even test out its nuclear weapon. The attack of Hiroshima and Nagasaki during the Second World War helped project the US as the most powerful power.

But the development of nuclear arms by the Soviet Union led to competition for the world power. The Soviets developed their own atomic bomb and tested its very first atomic bomb in 1949. This nuclear test codenamed "RDS-1" or "First Lightning" at the Semipalatinsk test site in what is now modern-day Kazakhstan led to the race for power especially between the United States and the Soviet Union.

Thus, the correct answer is the second option.

battle of survival between farmers and the rabbits during the great depression