CBSE Class 7 Science Fibers from Animals Assignment

Q A. Answer the following questions:

1) Explain the following terms:

i) Incubator ii) Moulting iii) Cocoon iv) Raw silk v) thrown silk vi) Weighting vii) Exotic breeds

2) Mention various types of silks.

3) How would you judge the quality of wool?

4) Explain the process of shearing.

5) Write a test by which you can differentiate silk and wool from artificial fibres.

6) What is ‘cross breeding’? Why is it done?

Q B. Fill up the blanks:

i) Dorset and Soviet are the examples of …………… breeds of sheep.

ii) The Marwari, Lohi, Nali etc. are the ……………... breeds of sheep which give high yield in wool every year.

iii) Wool starts changing its colour at ………….. degree Celsius.

iv) The thrown silk is bleached generally by a dilute solution of ………………

v) Each silk moth lays ………. no. of eggs in the bag and dies.

vi) During the feeding period, a silkworm sleeps ………….times at the intervals of about six days.

vii) …………… , …………. and ……………. are some animals which yield wool other than sheep.

viii) The people who throw the silk , are called ……………… .

ix) Tiny knots found on clipped wool are called ………………….. .

x) Wool absorbs ………………. water than any other fibre.