(a) Silk and wool fibres are obtained from animals.

Fibres are obtained from plants as well as animals. The example of fibre obtained from plants is cotton fibre (obtained from cotton plants). The examples of fibres obtained from animals are silk and wool.

•Silk fibre is obtained from silk moth.

•Wool fibre is obtained from fleece (hair) of sheep/yak/goat.

(b) Silk fibres come from cocoon of silk worm.

Silk fibres come from the cocoon of silkworms. Silkworm completely covers itself by silk fibres. This covering is known as cocoon. When cocoons are boiled/ exposed to steam, the silk fibres separate out.

(c) Wool yielding animals bear fleece (hair) on their body.

Wool comes from varieties of animals such as sheep, yak and goat. These wool-yielding animals bear hair on their bodies. These hairs keep these animals warm in cold weather. These hairs are removed for obtaining wool fibre.

(d) Hair trap a lot of air, which is a poor conductor of heat.

Animals have thick coat of hairs. These hairs keep them warm. This is possible because thick hairs trap a lot of air in them. Air is a poor conductor of heat i.e. air prevents the loss of heat from their bodies.