Cotton itself is not a stretchy fiber. Woven fabric is typically not stretchy. So no, I would not expect a cotton gauze to be stretchy unless it was a cotton blend.

They are somewhat stretchy.. But don't force them to stretch further then they are supposed to go.

No, it is made stretchy by either chicle or sometimes (ew) rubber.

Stretchy elastic seems to be a trick question for a quiz given in Econ at UP - stretchy elastic is the band around your stomach on a pair of sweats. Good luck out there.

No.

Hotglue isn't stretchy, and bike tubes, and patches are. Sticking something stretchy onto something stretchy with a stiff glue isn't going to work.