How did trade strengthen the relationship between the colonies and britain? How did it influence it?
There are many sides to that question. Trade between G. Britian and her colonies made her the greatest power both economically and politically in the world. These site may give you some help seeing all the sides.
http://www.bbc.co.uk/radio4/history/empire/episodes/episode_77.shtml
http://en.wikipedia.org/wiki/British_Empire#Free_trade_and_.22informal_empire.22
http://www.tax.org/Museum/1756-1776.htm