help on I-485 RFE

I got a I-485 RFE. There is a lot of information in the notice. But only one box was checked and actually fits my case.
I have two questions:
1. I did send my marriage certificate when I filed my application, why do they ask for it again?
2. I just need to take care of the evidence led by the checked box, right? Dont know why they cannot just type "need your marriage certificate' instead of sending a lot of junk information that has nothing to do with my case
thanks