1. What was the arms race?

2. Why weren't nuclear weapons ever used during the cold war?

 1. The arms race was basically a competition for supremacy in nuclear warfare.  2. The price was very high for nuclear weapons and the other side would just retaliate back and kill more innocent people.

Explanation

might be agreeing to participate ethically with other european nations in the slave trade

or notifying other european nations when taking possession   of african territories

your answer will most likely be a.