Question

do all worms produce silk,if not why?

Answer 1

No all the worms do not produce silk as all the worms do not have special glands situated near the head that produce the thin silk filaments.
Silkworms possess a pair of specially modified salivary glands called sericteries, which are used for the production of fibroin – a clear, viscous, proteinaceous fluid that is forced through openings called spinnerets on the mouthpart of the larva.