Alright so i was looking at the features for this movie, and it said:
Special Edition Blu-Ray/DVD Combo
- Audio Commentary w/ Rob Pattinson & Kristen Stewart (both DVD & Blu-Ray sides)

When it says "both dvd & blu-ray sides" what does that mean? That i can view this on dvd and bluray? or that its on the normal dvd version of this movie too?

and then it says:
- Eight Deleted & Extended Scenes (Blu-Ray side only)

"Blu-ray side only" again what does this mean? and how is it different than the normal dvd?

Thanks for alll your help.