The first answer is actually simple. The reason is because the constitution allows it. Other than this simple answer, another reason is because it's fair. What I mean by "fair" is that the final decision would be completely unbiased, not giving any advantages to both parties.
The second question is completely your opinion. Generally speaking, most people could care less about jury duties of any kind.
The third question depends on where you live. Like the question says, just google it.
I would also recommend going back to the pages of the book (38-40). My answers may not be necessarily correct depending on what the textbook you're using states.
