NCERT Class VII: Science-Exercise Solutions

NCERT Book Page Number-32
Q.1. You must be familiar with the following nursery rhymes:
(i) ‘Baa baa black sheep, have you any wool.’
(ii) ‘Mary had a little lamb, whose fleece was white as snow.’
Answer the following:
(a) Which parts of the black sheep have wool?
(b) What is meant by the white fleece of the lamb?
Answer:
(a) Wool is obtained from the hairy fibres (hair) of the sheep.
(b) White fleece of the lamb refers to the white coloured hair of the lamb.
Q.2. The silkworm is (a) a caterpillar, (b) a larva. Choose the correct option.
(i) a
(ii) b
(iii) both a and b
(iv) neither a nor b
Answer: (iii) both a and b
Q.3. Which of the following does not yield wool?
(i) Yak
(ii) Camel
(iii) Goat
(iv) Woolly dog
Answer: (iv)Woolly dog

Q.4. What is meant by the following terms?
(i) Rearing
(ii) Shearing
(iii) Sericulture
Answer:
(i) Rearing: Rearing means helping someone to grow up.
(ii) Shearing: It is the process of removal of fleece along with a thin layer of skin from the body of sheep.
(ii) Sericulture: Sericulture refers to the rearing of silkworms to obtain silk.
Q.5. Given below is a sequence of steps in the processing of wool. Which are the missing steps? Add them.
Shearing, __________, sorting, __________, __________, __________
Answer:
Shearing, __scouring__, sorting, __picking of burrs__, __dying of fibres__, making of yarn__

Q.6. Make sketches of the two stages in the life history of the silk moth which are directly related to the production of silk.
Answer: The two stages in the life history of silk moth directly related to silk production are

Q.7. Out of the following, which are the two terms related to silk production?
Sericulture, floriculture, moriculture, apiculture and silviculture
Hints: (i) Silk production involves cultivation of mulberry leaves and rearing silkworms.
(ii) Scientific name of mulberry is Morus alba.
Answer:
Sericulture and moriculture
Q.8. Match the words of Column I with those given in Column II:

Answer:

NCERT Book Page Number-33
Q.9. Given below is a crossword puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete the words.
Down Across
(D) 1: Thorough washing (A) 1: Keeps warm
2: Animal fibre 2: Its leaves are eaten by silkworms
3: Long thread like structure 3: Hatches from egg of moth

Answer: