Question

Silk fibres are secreted by _______.
A. Larva
B. Pupa
C. Cocoon
D. Adult silk moth

Answer 1

Hint: Silk is a natural macromolecule fiber. The known silk is obtained from the cocoons of the larvae of the mulberry silkworm moth raised by a process called sericulture.

Complete answer:
Silk is a natural macromolecule fibre, some sorts of which may be woven into textiles. The macromolecule fibre of silk consists of fibroin which is made by bound insect larvae to create cocoons. The known silk is obtained from the cocoons of the larvae of the mulberry silkworm moth reared in captivity (sericulture). The shimmering look of silk is due to the triangular prism-like structure of the silk fibre, that permits silk textile to refract incoming lightweight at completely different angles, therefore manufacturing completely different colours. Silk is made by many insects; however, the silk of lepidopterous insect caterpillars has been used for textile producing. There has been some analysis of alternative kinds of silk. Silk is principally made by the larvae of insects undergoing complete metamorphosis; however, some insects, like web spinners and gravelly crickets, turn out silk throughout their lives. Silk production additionally happens in Hymenoptera (bees, wasps, and ants), silverfish, mayflies, thrips, leafhoppers, beetles, lacewings, fleas, flies, and midges. Alternative kinds of arthropods turn out silk, most notably numerous arachnids, like spiders.
Hence, the correct answer is option C.

Note: A cocoon may be a tiny and scrotiform protection layer woven by silkworms. There are many kinds of cocoons, most of which are white or soft yellow and have oval or spherical shapes. A silk cocoon contains a length of about 3-4 centimetres.