is core to the notion of “life, liberty and the pursuit of happiness” in the Declaration of Independence

Answer 1

the idea that government may never restrict citizens’ liberty

Answer 2

I don't think so. The government can restrict our liberty in certain situations. For instance we can't drive 50 mph in a 30 mph zone.

Answer 3

Human agency

Answer 4

The meaning of those words can be interpreted in many ways. A good explanation of the roots of the idea is here:

http://en.wikipedia.org/wiki/Life,_Liberty_and_the_pursuit_of_Happiness

Answer 5

the concept of American exceptionalism