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.
Materials (i assume you mean clothes of fabrics) are stretchy due to the amount of elastic in the fabric. More elastic means stretchier fabric, less elastic means it will not be as stretchy.
it is stretchy
yes.......................it is a stretchy elastic rubber band
flexible, springy, stretchy, plastic
elastic felt and rubber
elastic
elastic connective tissue
they are elastic and stretchy
a stretchy clause
Collegen
elastic (a stretchy string)
Something that can get longer than it's original size