Answer: Option D. -> thermocol
:
D
Fibre is a very thin, thread-like strand from which a material is made. It is categorized under two categories:
1. Natural fibres
2. Synthetic fibres
Nylon and polyester are examples of synthetic fibres and silk is a natural fibre obtained from cocoon of silkworm. Thermocol is not a thin, thread like strand. It is not a fibre.

Answer: Option D. -> Sorting
:
D
Sorting is done after scouring to separate hairs of different textures and types. This is to separate the low and high quality fibres of wool. The figure given below is an image showing sorting of wool.

Answer: Option C. -> scouring
:
C
Scouring is the process of washing the sheared hair. The woolen fibres are thoroughly washed in big tanks to remove grease, dust, and dirt manually or by machines.

Answer: Option C. -> silkworm
:
C
Silk is a natural fibre as it is obtained from caterpillars (larva or silkworms of silk moth of the family, Bombycoidea). Different groups of silk moths are used to produce wild silk, but the silk cultivated from larvae of the mulberry silkworm moth, Bombyx mori, accounts for most commercial production.

Answer: Option D. -> Silk
:
D

Silk is the natural fibre obtained from the cocoons of the silkworms. All of the other given options: Nylon, Dacron and Acrylic are man-made fibres.

Answer: Option C. -> Bacteria
:
C
The wool industry is one of the most important means of livelihood for many people. The sorter's job is very risky as they might get infected by a bacterium, anthrax, which causes a fatal blood disease called sorter's disease. Such types of diseases are called occupational hazards.

Answer: Option C. -> shearing
:
C
$\bullet$ Shearing is the first step involved in the processing of wool. In this process, fleece of the sheep is removed along with a thin layer of its skin.
$\bullet$ Sheared skin of the sheep is washed to remove grease, dirt and dust. This process is called scouring.
$\bullet$ The scoured wool is then sorted into coarse and soft wool, by the process of sorting.
$\bullet$ The sorted wool fibres are then dyed in different colours, before the yarn is made. This process is called dyeing.

Answer: Option A. -> True
:
A

The hairy skin of the sheep has two types of fibres that form its fleece: (i) the coarse beard hair, and (ii) the fine soft under-hair close to the skin. The fine hair provides the fibres for making wool because it is soft enough to wear.

Answer: Option C. -> Under-hair    
:
C

There are two types of sheep hair – the coarse beard hair which is on the top and the fine soft under-hair, which is close to the skin. This fine-soft under hair provides the fibre to make fine, soft wool.

Answer: Option A. -> True
:
A
After the larvae of silkmoths feed on the mulberry leaves and grow in size, they secrete a kind of fibrous protein which hardens around it like an enclosure. This silk fibre covering over silkworm is known as cocoon.