Colleen has just graduated from college, and while she is looking for her first "real" job her parents have agreed to let her move back in with them so she can save some money. colleen would be referred to as a kid while living in her parents' home.

The correct answer is boomerang.
Boomerang kids are those children, adolescents, or adults, who come back to live with their parents after a period of living apart. In the case above, Colleen has probably been living in a dorm, or campus while she was studying at her college, but now that she's graduated, she wants to come back and live with her parents until she finds a job.

It allowed for things to be produced much more quickly and efficiently 

Clean air provides nitrogen