When i backup my Itunes. Does it save my apps and the memory in my apps?

I have to backup my Iphone 4 to Itunes because i'm afraid it's going to break again. I don't want to lose my information in my apps. Cause i have a music app with over 300 songs and i don't want to lose them and have to re download them? Any help

Yes, they do. All you have to do is click sync apps and app data, it's all fixed.