Lord of the Flies help on a question!

Why is Ralph not to blame for the ending of the book; Lord of the Flies?

I have all my points. My theory is that he is only partly to blame. The others that are to blame are Jack and the adult society, I just need help with coming up with 3 quotations for each person.

The points I'm using is that Jack is stubborn and doesn't want to give up his pride -- making him to blame for the way things ended in the novel. He doesn't have any proper priorities because he does not want to be saved first, he wants to have fun. His age also plays a factor because he's not mature enough to understand as well as he uses his older age against the others to lead everyone.

Next, I'm going to say that the adults are at war themselves. I need help elaborating on this too. I need 2 more points.

Finally, Ralph is to blame because he lacks the confidence to lead the pack of people; he is extremely doubtful. He has no leadership qualities; not assertive, is not able to control the littluns and people on the island etc. And lastly, he is not solely responsible for the way things ended because he has good morals. He tried to make sure all the needs were met, making sure to go the more logical and responsible route. He showed genuine care throughout the novel for wanting to find actual help.

Now that I've got most of the points, what quotes could fit and the missing points for this question? Thanks. Please reply asap!