Class 8 Science - Chapter Crop Production and Management NCERT Solutions | Complete the following word puzzle with

Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.

If wheat is sown in the kharif season, what would happen? Discuss.

Write a paragraph in your own words on each of the following.
  (a) Preparation of soil                 (b) Sowing
  (c) Weeding                                (d) Threshing

Explain how fertilisers are different from manure.

Match items in column A with those in column B.
               A                                       B
  (i) Kharif crops                    (a) Food for cattle
  (ii) Rabi crops                     (b) Urea and super phosphate
  (iii) Chemical fertilisers       (c) Animal excreta, cow dung urine and plant waste
  (iv) Organic manure           (d) Wheat, gram, pea
                                             (e) Paddy and maize

Give two examples of each.
(a) Kharif crop
(b) Rabi crop

Explain how soil gets affected by the continuous plantation of crops in a field.

What is irrigation? Describe two methods of irrigation which conserve water.

What are weeds? How can we control them?

Select the correct word from the following list and fill in the blanks.
                 float, water, crop, nutrients, preparation

(a) The same kind of plants grown and cultivated on a large scale at a place is called _____________.
(b) The first step before growing crops is _____________ of the soil.
(c) Damaged seeds would _____________ on top of water.
(d) For growing a crop, sufficient sunlight and _____________ and _____________ from the soil are essential.

Which of the following can be beaten into thin sheets?
  (a) Zinc     (b) Phosphorus     (c) Sulphur     (d) Oxygen

Fill in the blanks
(a) Most liquids that conduct electricity are solutions of , ______________ and ______________.
(b) The passage of an electric current through a solution causes ______________ effects.
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the terminal of the battery.
(d) The process of depositing a layer ofany desired metal on another material by means of electricity is called .

Give two examples each of situations in which you push or pull to change the state of motion of objects.

Fill in the blanks:
(a) Friction opposes the _____________ between the surfaces in contact with each other.
(b) Friction depends on the _____________ of surfaces.                                                                                                                                                                      (c) Friction produces __________.
(d) Sprinkling of powder on the carrom board ________ friction.
(e) Sliding friction is ___________ than the static friction.

List conditions under which combustion can take place.

Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have one-celled body. (T/F)
(b) Muscle cells are branched. (T/F)
(c) The basic living unit of an organism is an organ. (T/F)
(d) Amoeba has irregular shape. (T/F)

Which of the following cannot be charged easily by friction?
(a) A plastic scale
(b) A copper rod
(c) An inflated balloon
(d) A woollen cloth.

Fill in the blanks:
(a) A place where animals are protected in their natural habitat is called                  .
(b) Species found only in a particular area is known as                          .
(c) Migratory birds fly to far away places because of                     changes.

Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.

What are the different ways in which water gets contaminated ?

Mention against each of the following whether regular or diffused reflection will take place when a beam of light strikes. Justify your answer in each case.
(a) Polished wooden table (b) Chalk powder
(c) Cardboard surface        (d) Marble floor with water spread over it
(e) Mirror                            (f) Piece of paper

Can you store lemon pickle in an aluminium utensil? Explain.

Suppose your writing desk is tilted a little. A book kept on it starts sliding down. Show the direction of frictional force acting on it.

In which female reproductive organ does the embryo get embedded?

Sketch larynx and explain its function in your own words.

In order to meet the ever-increasing demand in factories and for shelter, trees are being continually cut. Is it justified to cut trees for such projects? Discuss and prepare a brief report.

Explain the process of formation of petroleum.

Explain how you can take care of your eyes.

Choose the correct option.

(a) Adolescents should be careful about what they eat, because
(i) proper diet develops their brains.
(ii) proper diet is needed for the rapid growth taking place in their body.
(iii) adolescents feel hungry all the time.
(iv) taste buds are well developed in teenagers.

(b) Reproductive age in women starts when their
(i) menstruation starts.
(ii) breasts start developing.
(iii) body weight increases.
(iv) height increases.

(c) The right meal for adolescents consists of
(i) chips, noodles, coke.
(ii) chapati, dal, vegetables.
(iii) rice, noodles and burger.
(iv) vegetable cutlets, chips and lemon drink.

What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?