visa3310

Also what if there was no marriage between parents???

I am working on filing the FOrm I-130 online and the online form is pretty lengthy I am only filing for my dad but the form is asking to provide information about parent two and also asking for marriage certificate etc but am only filing for my dad, so can i just skip adding information about parent 2? One will think they will make the form such that it will have conditionals like if one is filling for both parent or not and ask questions based on that but no, the dumb people behind the website just lack cognitive logic, but that is alright. So anyone here willing to answer this? I will think the only evidence here will be dad birth certificate and mine and whatever else related to showing proof between me and my dad not some marriage certificate Please advice