Which group made up the majority of the roman population and became citizen-soldiers during time of war

The Plebeians

Explanation:

The Roman population was conformed by two classes, the Patricians and the Plebeians, The Patricians class was the early Roman empire ruling class and it was conformed by a small percentage of the Roman population, the other remaining percentage of the population was the Plebeians whom around 494 BC began a fight against the rule of the Patricians in a protest strike called the "Conflict of Orders."

i believe it is capitalists.  

the correct answer is:   the domino theory states that if one country in a region came under the influence of communism, then the surrounding countries would follow in a domino effect.