Question

At which stage in its life cycle does the silkworm yield the fiber of commercial use

Answer 1

Silk worm yields silk fibre when it is in its cocoon.
These cocoons are then boiled in water in industries to kill the silk worm and to get silk from their cocoons.

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Answer 2

When the silkworm is a cacoon then it gets ready to yield the silk fibre for the commercial use.

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