...for "what problems did the rabbits encounter in building a new warren in the book watership down"�I implore you to read the book yourself and find out!
Did a teacher assign it for summer reading? It's too soon, surely, for you to have been assigned a paper for this semester's classes.
Listen, even if you blow the back-to-school quiz, don't hold that against the book. Give it a try.
You've never met anyone like Hazel and Fiver. Or Bigwig and Kehaar. You want them in your your life, trust me.
I guarantee you the "problems they encountered" aren't the sort of challenges you might anticipate. They aren't easily boiled down to quiz answers, either. Those rabbits' experiences will make your heart pound, and they'll heat up your brain, too, because what happens down in those warrens is, well, human history.
But wait, if I start spouting in that direction you'll never pick up the book. Let's just stick with the fact that it's a tremendously gripping story. With characters who will burrow into your heart and live there forever.
I know I'm too late. You already landed on my site and Googled right back out again, not having found your pat answers here. (Or there.)
I hope that wherever you wound up, there was something in the information you cribbed that made you want to go back and read the book yourself. Not for a grade, not because you had to, but because some essay you skimmed about Hazel-rah, an average rabbit who was surprised by his own capabilities, whispered to you that you, too, might have latent strengths and gifts to call upon when life bares its pointed teeth at you.