Radio is the technology of utilizing radio waves to carry data, such as sound, by regularly changing characteristics of electromagnetic energy waves conveyed through space, such as their amplitude, wavelength, phase, or pulse width. When radio waves hit an electrical wire, the oscillating tracks produce an alternating current in the conductor. The data in the waves can be obtained and converted back into its initial form.
An economic reason for the institution of serfdom was to maintain a "stable work force," since this kept most of the workers in their "place" without much trouble.
The correct answer should be the Sons of Liberty
This was a secret society that was formed in the thirteen colonies in order to fight taxation without representation in the colonies. They were famous for their fight against the stamp act in 1765 and they disbanded when they actually managed to repeal the stamp act. Many took their name when they later fought in the war of independence.
Cornell notes is the answer