Question [Q] Some basic nexus 4 help

Hello. I have a couple questions about my nexus 4. It's running paranoid android newest update. It asked me if I wanted to enable recent app card stack view and I clicked yes by mistake. I was wondering how to set it back? Also my phone when playing music changes the lock screen wallpaper to whatever album I'm listening too is there a way to make it so it don't change?

If anyone can help it will be greatly appreciated. Thank you.