What are their extent?
Define them for me.
How about let's all see YOU do that.
Two of the most important and appallingly unaddressed questions of our age.
Here's my best answer, (but I understand that it probably isn't perfect):
Rights are those things that any free adult individual can assert, that the government can guarantee (or direct compensation/retribution if violated) equally for all, and that does not trespass upon the Rights retained by others.
I could assert the Right to pick my nose, and it does not trespass upon the Rights of others, but the government can't guarantee that Right if I have no arms or fingers. Therefore, it is not a Right.
Animal Rights do not exist, because there is no way to monitor and guarantee them for all animals.
Group Rights and preferential treatments like AA are not Rights, because I cannot assert some of them due to the circumstances of my birth (gender, skin color, etc).
I'll take a shot, since no one else seems interested.
A right is anything you must do to sustain/better your life - but only if that action does not run counter to another person's ability to do the same. Your rights are the same as everyone else's, and you need ask no one for permission to exercise them. You could choose to collaborate with other individuals if you feel your collective actions will better your life, or you can choose to act alone.
Incidentally, a right can never be a claim on another person's time, intellect or property. Rather it can only be actions you take yourself or with consent of another person.