You can't really directly relate different competitions among different states and regionals. This event at most competitions is probably going to mainly be fill in the blank/short answer with maybe some multiple choice, though. The difficulty and the topics covered is up to the individual event supervisors. Some might make an invitational test that is more difficult than a national test, and others could make a state test that's easier than most regionals.
Events: Ecology, Herpetology, Cell Bio, Entomology, Sounds of Music, Circuit Lab, Chem Lab, Disease Detective, Dynamic Planet, Five Star, EggONaut, Enviro Chemistry, Fermi, Quantum Quandaries!
Nationals: Wichita: Ecology-4, Entomology-5, Team-11; DC: Sounds-1, Team-11