Class 8 Science - Chapter Reproduction in Animals NCERT Solutions | Explain the importance of reproduction i

What is metamorphosis? Give examples.

Define asexual reproduction. Describe two methods of asexual reproduction in animals.

Complete the cross-word puzzle using the hints given below

Across
    1. The process of the fusion of the gametes.
    6. The type of fertilization in hen.
    7. The term used for bulges observed on the sides of the body of Hydra.
    8. Eggs are produced here.

Down
    2. Sperms are produced in these male reproductive organs.
    3. Another term for the fertilized egg.
    4. These animals lay eggs.
    5. A type of fission in amoeba.

How are test tube babies born?

How are babies produced through IVF technique? What are such babies called?

Differentiate between internal fertilization and external fertilization.

Describe the process of fertilization in human beings.

Give two difference between a zygote and a foetus.

In which female reproductive organ does the embryo get embedded?

How is an embryo developed?

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 ?

Describe with the help of a diagram an instrument which can be used to detect a charged body.

Iqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor. Who will have to apply a larger force and why?

Make sketches of animal and plant cells. State three differences between them.

Make a sketch of the human nerve cell. What function do nerve cells perform?

Fill in the blanks in the following :
(a) A person 1 m in front of a plane mirror seems to be _______________ m from his image.
(b) If you touch your ____________ ear with right hand in front of a plane mirror it will be seen in the mirror that your right ear is touched with ____________
(c) The size of the pupil becomes ____________ when you see in dim light.
(d) Night birds have ____________ cones than rods in their eyes..

‘Cells are the basic structural units of living organisms’. Explain.

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.

Where are chromosomes found in a cell? State their function.

Name the forces acting on a plastic bucket containing water held above ground level in your hand. Discuss why the forces acting on the bucket do not bring a change in its state of motion.

Explain why objects moving in fluids must have special shapes.