Answer:
The correct answers are:
1. Spies were used to uncover national secrets.
3. Competition took place outside of warfare.
4. Proxy wars were supported around the world.
Explanation:
The cold war involved a thousands of spies from both the US and it's allies and the Soviet Union and their allies. Many of these were able to infiltrate deep into each other's government to find national secrets.
Competition in the cold war took place outside of military and warfare. This included the education, technology and global soft power. The most famous example of this is the space race between the US and the Soviet Union which the US eventually won by being the first country to send a man on the moon.
Both countries were nuclear powers and never fought a direct war. However, they did fight numerous proxy wars all over the world, including Vietnam, Afghanistan, Cambodia, South America etc.
