Help Understanding A journey to the center of the earth by: Jules Verne.

1.)What problems do each of the 3 characters face within themselves, and how do they end up resolving each of there problems?

2.)What are 4 of the most important occurences in the book that really make a difference?

3.)What are 4 symbols within the story?

4.)What are 4 major themes within this story?

5.)What are 4 lessons you can learn within this story?

If anyone could help me It would be greatly appreciated. I just finished this book but had a hard time understanding several parts of the story.