Answer:
unique or famous
but I think mainly unique
"I can't come with you as I am too busy."
An arms race is a situation in which two or more countries or groups of countries are continually trying to get more weapons and better weapons then the other groups in case of a possible attack.
An arms race
I am pretty sure it would be massive because it is an English question. If you are doing a multiple choice question you should see which one fits the best. If could also be positive impact.
