The web beacons are one of the different techniques, that are used on web pages and emails, to check whether a user has access to some unobtrusively. It is a line, that is often invisible, and typically does not exceed 1 pixel.
It is usually used with cookies.
It is also known as a small graph, which generates a request to the server for tracking service.
B) Raw materials; As stated, European powers did indeed grow more industrialized, therefore they needed more raw materials. The North provided lumber, spent time whaling, etc.. The South spent time growing cash crops such as rice, cotton, and indigo.