What was one positive effect of the Cold War for the United States and the Soviet Union? Both countries developed space programs.
Both countries developed hydrogen bombs.
Both countries gained intelligence about each other.
Both countries had a proliferation of nuclear weapons.

Explanation:

an arms race occurs when two or more countries increase the size and quality of military resources to gain military and political superiority over one another. The Cold War between the United States and the Soviet Union is perhaps the largest and most expensive arms race in history; however, others have occurred, often with dire consequences. Whether an arms race increases or decreases the risk of war remains debatable: some analysts agree with Sir Edward Grey, Britain's foreign secretary at the start of World War I, who stated "The moral is obvious; it is that great armaments lead inevitably to war."

Dreadnought Arms Race

With the Industrial Revolution came new weaponry, including vastly improved warships. In the late nineteenth century, France and Russia built powerful armies and challenged the spread of British colonialism. In response, Britain shored up its Royal Navy to control the seas.

Britain managed to work out its arms race with France and Russia with two separate treaties. But Germany had also drastically increased its military budget and might and built a large navy to contest Britain’s naval dominance in hopes of becoming a world power.  

to find facts and details to use as evidence