CBSE 7th Class Solutions, Class 7th Science
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NCERT Solution Class 7th – Chapter 3 – Animal Fibre

We  have prepared the detailed solution of class 7th Science Chapter 3 – Animal Fibre, All the answers are prepared by Expert teachers and are very useful for all the board using NCERT like CBSE, State boards.

you can check Previous Chapter Solutions here –

Also Class 7th Science All chapters solutions here –

Exercise -1st Brief answer

Question -1  How does wool help in keeping out body warm?

Solution–  Wool is a good fibre for making clothes for the following reason ;-

[1] Wool is soft and provides  warmth

[2] The air scapes between  The wool fibre  creat an insulating barrier .Which prevents body heat from escaping .

Question -2 What  is selective breeeding ?  

Solution- Selective breeding is a method that has been practied for many hundreds of year to get plants or animals with desired characteristics .

Question-3 Name the kind of of sheep found in  rajasthan?

Solution-  Lohi and Marvari

Question -4 How is Wool removed from the sheep ?

Solution –  Shering  can be done  by hand using large Razors or Dippers or by machine

Question -5 What characterise are used to decide  the quality of Wool?

Solution – The  thickness lenght  sheen strenght and colour   of the hair detrimne the quality of wool

Question- 6  At   What  stage is wool dyed?

Solution – The fibre are dyed in any desired colour  since wool can be dyed easily dyeing process  can be done at any stage 

Question- 7 Name any four animal other than sheep that we get Wool from?

Solution – Four Animals  other than sheep that we get wool from are goat ,  camel , rabbits and alphaces

Question -8 Name  the  four stages of the silk moth of life cycle?

Solution –  The four stages of the silk moth life cycle are eggs  ,larva , pupa and adult

Question -9  How  much time does the silkworm  larva undergo moulting? 

Solution – The silk worm larva undergo moulting in four times

Question -10 name any two diseases ?

Solution – Ashtama and broniches

Exercise -2nd  Answer in long 

Question -1  Why is wool a good fibre  for making winter clothes?

Solution – Wool is  soft and provides warmth The air scapes between the wool fiber create an insculating barrier  which prevents body heat from escaping winters

[1] Wool has elasticity

[2]  It  can be easily dyed in different colours

Question -2 Write a short note on the process of obtaing wollen clothes from sheared wool?

Solution – One of the preferred method to make woolen  yarn into cloth is knitting this is done by knotting  needs machines

Question – 3 Explain the life cycle of silk moth?

Solution –  [1] The female  silk  moth lays about 300 -400 eggs at a time Which hatch Within 7-14 days The egg stage forms  the first part in the silk moth life cycle

[2] When an  egg hatches a silkworm crawls out this as the larva  can feed on  tender   mulberry  leaves   How ever during the growth phase it can eat eat tougher mulberry leaves as weel  the larva stage for about  21 days

[3]  Eventually the larva prist builds a web around itself to support its body it then starts scereting fine protiens

Question -4  how is the health of workers in the industry affected by the processused?

Solution  – [1] Respiratory diseases such as asthame and bronchies are common because the workers are exposed to foul smelling  vapors while steaming and reeling the silk fibre

[2]  They have to insert their unprocted hands into hot Water to hill the warm in the cocoons  this result in peeling of the skin which may led to skin infection

Exercise – 3rd  Multiple choice question

[1] Which of these is not a fiber?

[1] Cotton               [2]Wool             [3] Nylon      [4] leather

Answer – Leather

[2] Which of these is not an animal fiber?

[1] Wool         [2] silk          [3] Jute       [4] Mohair

Answer – Jute 

[3] Which of these is a syntheic fiber?

[1] jute                 [2] silk         [3]    rayon      [4] Cashmere

Answer – Rayon 

[4] The washing of fleece to remove  dust and dirt is called?

[1] Carding     [2] scouring        [3] grading    [4] Shering

Answer – Scouring 

[5] Rearing of silkworm on a large scale for the production of silk is known as 

[1] Sericulture          [2] Siliviculture     [3] hortculture       [4] floriculture

Answer – Sericulture

[6] The female silk moth lays eggs  Which hatches into

[1] cocoons            [2] Larvae               [3] Pupae               [4] moths

Answer – Larvae

Exercise – 4th   Fill in the blanks

[1] Nylon and rayon are _________ fibers?     [ Synthetic]

[2]  the process of straightening wool is called ________     [Carding]

[3] The fleece is separated based on the quality of fiber by the process of _________  [Grading]

[4] We get cashmere from the _________goat  [ kashmir]

[5]  The process by which a silkworm sheds its screen is called _________ [Moulting]

[6] Silkworm feed on _______ leaf   [Mulberry]

Exercise -5th – True or false

[1] Wool trap more heat than cotton [True]

[2] It is better to wear light coloured clothes on a hot day than darken clothes [True]

[3] Fur is a natural fiber [True]

[4] Wool is obtained only from sheep [False]

[5] Wool from sheep can only be removed after killing the animal   [False]

[6] Mohair is obtained from alpaca [False]

[7] The pupa in the cocoon is killed before Relling the silk [True]

[8] Silk workers  often suffer from asthma [True]

you can check All Chapters Solutions here –

Also Class 7th Science All chapters solutions here –

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