NCERT Exemplar for Class 7 Science Solutions Chapter 3 Fibre to Fabric

Multiple Choice Questions

1. The rearing of silkworms for obtaining silk is called

(a) Cocoon

(b) Silk

(c) Sericulture

(d) Silviculture

Ans: The correct answer is option (c), sericulture. The rearing of silkworms for obtaining silk is called sericulture.

2. Which of the following is not a type of silk?

(a) Mulberry silk

(b) Tassar silk

(c) Mooga silk

(d) Moth silk

Ans: The correct answer is option (d), moth silk. Moth is a silkworm. So, moth silk is not a type of silk.

3. Paheli wanted to buy a gift made of animal fiber obtained without killing the animal. Which of the following would be the right gift for her to buy?

(a) Woollen shawl

(b) Silk scarf

(c) Animal fur cap

(d) Leather jacket

Ans: The correct answer is option (a), woollen shawl. Wool is extracted from animals such as sheep without killing them.

4. Silk fiber is obtained from

(a) Fleece of sheep

(b) Cotton ball

(c) Cocoon

(d) Shiny jute stalk

Ans: The correct answer is option (c), cocoon. To obtain the silk fibers “cocoon‟ of silk moth are used.

5. Wool fiber cannot be obtained from which of the following?

(a) Goat

(b) Llama

(c) Alpaca

(d) Moth

Ans: The correct answer is option (d), moth. Wool fiber can be obtained from animals such as camel, sheep, yak, goat, rabbit, etc. Moth is a type of an insect.

6. Selective breeding is a process of

(a) Selecting the off springs with desired properties.

(b) Selecting the parents with desired properties.

(c) Selecting an area for breeding.

(d) Selecting fine hair for good quality wool.

Ans:  The correct answer is option (b). Selective breeding is a process of selecting the parents with desired properties.

7. The general process that takes place at a sheep shearing shed is

(a) Removal of fleece.

(b) Separating hair of different textures.

(c) Washing of sheep fiber to remove grease.

(d) Rolling of sheep fiber into yarn.

Ans:  The correct answer is option (a), removal of fleece. Shearing is termed as a removal of fleece from sheep. This process will be done by shearing machine or manually by razors.

8. The term sericulture is used for

(a) Culture of bacteria.

(b) Rearing of silkworm.

(c) Making silk fabric from silk yarn.

(d) Production of sarees.

Ans: The correct answer is option (b). The term sericulture is used for describe rearing of silkworm.

9. Reeling of silk is

(a) A process of making silk reels.

(b) Spinning of silk fibers.

(c) Weaving of silk cloth.

(d) The process of taking silk threads from cocoon.

Ans: The correct answer is option (d). Reeling of silk is the process of taking silk threads from cocoon.

10. Silkworms secrete fiber made of

(a) Fat

(b) Cellulose

(c) Protein

(d) Nylon

Ans: The correct answer is option (c), nylon. Silkworms secrete fiber made of protein.

Very Short Answer Questions

11. Fill in the blanks in the following statements.

(a)________and________fibers are obtained from animals.

Ans: Silk, wool

(b) Silk fibers come from of silk.

Ans: cocoons, moth

(c) Wool yielding animals bear on their body.

Ans: hair

(d) Hair traps a lot of, which is a poor of heat.

Ans: air, conductor

12. State whether the following statements are true or false. If false, correct them.

(a) Silkworms are caterpillars of silk moths.

Ans: The given statement is true.

(b) In India, camels and goats are generally reared for obtaining wool.

Ans: The given statement is false. In India, sheep are reared for obtaining wool.

(c) The rearing of silkworms for obtaining silk is called silviculture.

Ans: The given statement is false. The rearing of silkworm for obtaining silk is called sericulture.

(d) In the process of obtaining wool from fleece, sorting is done after scouring.

Ans: The given statement is true.

(e) Yak hair is not used to make woollen fabric.

Ans: The given statement is false. Yak hairs are used to make woollen fabric.

13. How do the hairs of certain animals help in keeping their bodies warm?

Ans: On an animal body there are thick coats of hairs which helps to keep their body warm. These hairs trap a lot of air in them.

Short Answer Questions

14. Match the items of Column I with the items given in Column II.

Ans: Correct match of the given table:

15. Various steps involved to obtain wool from fleece are given here.

(a) Picking out the burrs

(b) Dyeing in various colours

(c) Shearing

(d) Scouring

(e) Sorting

Write the above steps in the correct sequence in which they are carried out.

Ans: The correct sequence in which they are carried out:

Step 1-(c) Shearing

Step 2-(d) Scouring 

Step 3-(e)Sorting

Step-4(a) Picking out the burrs

Step5-(b) Dyeing in various colours

16. Some words related with silk are jumbled up. Write them in their correct form.

(a) TURECULRISE

Ans: SERICULTURE

(b) WILSMORK

Ans: SILKWORM

(c) BELMURRY

Ans: MULBERRY

(d) RINGLEE 

Ans: REELING

17. Figure 3.1 shows three rings of circles with letters in them. Some of these letters in each ring can form the name of one wool-yielding animal. Find the names of these animals.

Ans: The animal's name is YAK in the innermost ring. The animal's name is CAMEL in the middle ring. The animal's name is SHEEP in the outermost ring.

18. Write a caption for each of the figures given as Figure 3.2 (a – d).

Ans: Figure (a): Eggs of silk moth on a mulberry leaf. 

Figure (b): Silkworm

Figure (c): Cocoon

Figure (d): Cocoon with developing moth.

19. Steps for the production of silk are given below in a jumbled order. Arrange them in their proper sequence.

(a) Eggs are warmed to a suitable temperature for the larvae to hatch from eggs.

(b) fibers are taken out from the cocoon.

(c) After 25 to 30 days, the caterpillars stop eating and start spinning cocoons.

(d) The larvae/caterpillars or silkworms are kept in clean trays along with freshly chopped mulberry leaves.

(e) Female silk moths lay eggs.

(f) Cocoons are kept under the sun or boiled in water.

Ans: The proper sequence of given statements are given below:

Step 1- (e) Female silk moths lay eggs.

Step 2- (a) Eggs are warmed to a suitable temperature for the larvae to hatch from eggs.

Step 3- (d) The larvae/caterpillars or silkworms are kept in clean trays along with freshly chopped mulberry leaves.

Step 4- (c) After 25 to 30 days, the caterpillars stop eating and start spinning cocoons.

Step 5- (f) Cocoons are kept under the sun or boiled in water.

Step 6- (b) fibers are taken out from the cocoon.

20. A wholesale woollen fiber dealer gets the woollen fiber of different textures sorted for various purposes. Match the items in Column I with the woollen fiber in Column II.

Ans: Correct form of given table:

Long Answer Questions

21. Complete the paragraph related to the life history of silk moth by filling in the blanks.

The(a)______silk moth lays(b)_________, from which hatch (c)_________called (d)_______or(e)___________. They grow in size and when the caterpillar is ready to enter the next stage of its life history called(f)___________, it first weaves a covering to hold itself, which is known as  (g)__________.

 Ans: (a) female (b) eggs, (c) larvae (d) caterpillars (e) silkworms. (f) pupa (g) cocoon.

22. Paheli went to the market to buy sarees for her mother. She took out a thread from the edge of the two sarees shown by the shopkeeper and burnt them. One thread burnt with a smell of burning hair and the other burnt with the smell of burning paper. Which thread is from a pure cotton saree and which one from a pure silk saree? Give reason for your answer.

Ans: A silk thread must be burnt to ascertain its purity. It's genuine silk if the burning perfume of the thread is equal to the burning smell of hair. Silk and hair have the same odour since they are both protein fibers.

A cotton thread must be burnt to assess the quality of the cotton. It's 100 percent cotton if the burning aroma of the thread is similar to the burning scent of paper. Cotton and paper both have a similar odour since they are both polysaccharides.

23. Explain the phrase – “Unity is Strength” on the basis of the making of fabric from fiber.

Ans: A single fiber is a single strand of material. A single fiber is too weak to be separated into two segments. It is difficult to shred a single cloth made up of many fibers. When compared to a single fiber, the fabric requires more force to pull apart.

24. Write various steps for processing fibers into wool.

Ans: The various steps for processing fibers into wool:

(a) Shearing: The procedure of removing fleece of sheep is termed as shearing.

(b) Scouring: The procedure of cleaning removed fleeces is termed as a scouring.

(c) Sorting: After the procedure of scouring, next step is sorting. In this procedure washed hairs are sent to the various factories. In the factories separation of different texture of hairs takes place.

(d) Picking out burrs: The tiny fluffy fibers that were picked out from fleece are known as blurs. After collecting all the blurs they were cleaned and dried again.

(e) Dyeing: In this process fibers are dyed into different colours.

(f) Rolling into yarn: The fibers are straightened, combed, and also, rolled into yarn.

25. Describe the life history of silk moth with the help of figures of various stages.

Ans: Figures depicting the silk moth's life cycle at various stages: 

It is the female "silk moth" who deposits the eggs. These eggs hatch into larvae. Their larvae are known as caterpillars or silkworms. These caterpillars/silkworms are fed fresh mulberry leaves. After that, the silkworm's size or shape changes, and it becomes a "pupa."

Pupa makes a cocoon to defend itself from predators at first. Within the cocoon, it develops into a moth. After that, it develops into an adult female or male silk moth.

NCERT Exemplar Class 7 Science Solutions Chapter 3 Fiber to Fabric

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