Page 30 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

E. Very short-answer questions.

1. Name the place where Angora goats are found in plenty.

Ans. Jammu & Kashmir, Himachal Pradesh and Uttrakhand are some place where Angora
goats are found in plenty.

2. Name the protein that hardens to become the silk fibre.

Ans. The protein that handens to became the silk fibre is called fibroin.
3. What is scouring?

Ans. The skin with hair is called ‘raw’ or ‘grease wool’ and is washed to remove dust

particles and dirt. This process is called scouring.
4. Which country leads the world in silk production?

Ans. China leads the world in silk production.

5. Name the bacteria which causes the disease anthrax.
Ans. The bacteria that causes the disease anthrax is Bacillus anthracis.

6. What are burrs?

Ans. Burrs are delicate, fluffy wool fibres.

7. Why does silk not crease or wrinkle easily?
Ans. Silk fibre has natural elasticity so it does not crease or wrinkle easily.

8. In which stage of making wool yarn is fleece passed through a series of rollers and

dryers to remove dust particles?
Ans. Scouring stage of making wool yarn is fleece passed through a series of rollers and

dryers to remove dust particles.

F. Short-answer questions.
1. What are the different sources of wool?

Ans. Wool is obtained from the hair of animals, such as goat, sheep and yak. These animals

have a thick coat of hair, called fleece, on their body to protect them from the cold

climate. Body hair helps to control body temperature. Hair trap air above the skin,
which helps to insulate the skin against heat loss. We use this hair is used to make

wool and warm clothes.

2. Why don’t cotton garments keep us warm in winters?
Ans. Cotton clothes are thin and do not have space in which air can be trapped. Thus

cotton clothes do not prevent heat coming out of our body. Woollen clothes keep us

warm during winter because wool is a poor conductor of heat and it has air trapped
in between the fibres.

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