To wear away is the same thing as erode. It usually refers to a natural phenomenon like the rock will eventually erode away.
The first one is a bit tricky. delegate can be a very like to delegate authority. It can also mean the voters at a democratic/republican convention. So the first one is delegate.
a person has the right to be tried jury of peers in a civil case. How does the Bill of Rights reflect the principle of "Limited Government"? it protects the basic rights and can't be taken away or be abused.
