The characteristics of different fibres are listed as

W: I am strong, elastic, light and burn slowly. I shrink on heating and form hard beads with smell of burning hair.

X : I burn completely leaving no residue.

Y : I can be woven like silk fibres and dyed in a wide variety of colours. I burn quickly with a smell of burning paper.

Z : I do not get wrinkled easily. I burn slowly and produce black smoke.

W, X, Y and Z are respectively: