key notes of chapter fibre to fabric class 7 serial wise
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Answer:
Natural fibres are obtained from plants and animals.
Silk comes from silkworm and wool from sheep, goat and yak. Hence, silk and wool are animal fibres.
Wool is obtained from the fur of the sheep, camel, llama, alpaca, yak and even goat and rabbit.
There are two ways of obtaining wool, by shaering the fur of the animal, or by collecting fallen and loose hair from the skin.
Silk is obtained fron the cocoons.
Sikworms or caterpillars are the larvae of the silk moth.
Silkworms take 3-7 days to prepare the cocoon, formed by concentris layers of a single thread.
About 2000 silkworms give a yeild of about 1/2kg of silk.
During their life-cycle, the worms spin cocoons of silk fibres.
There are several health hazards associated with sericulture, respiratory problems and skin infections being the major ones.
Sorters in the wool industry get infected by bacterium, called Anthrax, which causes a fatal disease called Sorter's disease.
Explanation: