Why did manufacturers hire children to work in their factories?

Tanya was used to using word, and she did some work for her brother mike, who was using wordperfect. tanya was quickly able to use wordperfect for windows with little difficulty, since many of the commands for it were the same as the commands for word. tanya's ability to use wordperfect best illustrates:

Census data is an example of: public information. private behavior. private information. public behavior.

What was the name of the theory that said that if one country in a region fell to communism, others would surely follow? 1) domino theory 2) arms race 3) brinkmanship 4) containment theory