Many major cities in the world today have large populations of people who have recently arrived; they have emigrated from other countries. Perhaps you, too, have left a familiar place to come to a new city or a new country. Or you may live in a city where there are large numbers of newcomers. Adapting to a new place forces people to seek out new friends, face new problems, and often learn a new language.



 According to the text,  

People are living longer in the United States. As a result, more and more middle aged adults are becoming caretakers of their aging parents. When their parents can no longer care for themselves, these adults stay at home to care for them in much the same way they cared for their own children. Playing the role of "parent sitter" is quite difficult and frustrating. For example, an aging parent may become blind. No longer able to see, the old person needs his or her children to perform many every day jobs. Another example is the parent who becomes brain damaged during the aging process. Natural roles are then reversed, as children are forced to care for their parents as if their parents were children. 



According to the text, the underlined words "parent sitter" refer to a person who