STD-3, CHAPTER-7: BIRDS AND THEIR NESTS, EXTRA QUESTION-ANSWERS

1.      Why are birds called as ‘aerial animals’?

Ans: Birds can fly in air. So, they are called aerial animals.

2.      Write the special features of birds that help them to fly.

Ans: Birds can fly in air, because they have,

i)   Hollow bones, which make their body light.

ii) Wings that are made up of light feathers.

iii)  Pointed, sharp, boat shaped body.

iv)  Tail, which helps them while changing the direction.

3.      Name some birds which cannot fly.

Ans: Penguin, ostrich, kiwi, are some birds which cannot fly. (others are, Steamer duck, Weka, Kakapo,  Takahe and Cassowary)

4.      Why are birds very light in weight?

Ans: Birds are very light in weight because their body is made up of hollow bones.

5.      Why penguin and some other birds cannot fly?

Ans: As penguins and some other birds have quite heavy bodies, so they cannot fly.

6.      How do the birds use their beaks and claws?

Ans: Birds use their beaks and claws to catch food and to build their nests.

7.      There are about ______ kinds of birds.

Ans: 10,000

8.      Name the smallest bird.

Ans: Humming bird is the smallest bird.

9.      Name the largest bird.

Ans: Ostrich is the largest bird.

10.  What is a nest?

Ans: A nest is a bird’s home.

11.  List some places where we find birds’ nests.

Ans: We find birds’ nests on trees, on the terraces of buildings, on electricity poles, on the top of almirah, behind the shelf, in the meter room and many other places.

12.  List some materials used by various birds to make their nests.

Ans: Different things like twigs, straws, leaves, feathers, cotton, small paper-bits, mud, wires and small wooden pieces, are used by various birds to make their nests.

13.  How are nests useful for birds?

Ans: i) Nests protect the birds from enemies and bad weather.

ii) Birds lay their eggs and hatch them in the nests.

iii) Birds keep their young ones safe and warm in their nests. The chicks stay there, till they are old enough to fly.

14.  Why do birds make sounds?

Ans: Birds make sounds,

                                          i)  to communicate about danger, food and

                                          ii) to locate one another.

15.  Birds start making their nests usually in the month of-

Ans: April

16.  Birds are very busy during the month of _____.

Ans: April

17.  Name three birds who work in pairs to make their nests.

Ans: The sparrow, sunbird and dove work in pairs to make their nests.

18.  Where can we find a sparrow’s nest?

Ans: We can find a sparrow’s nest, between the branches of a tree, on the top of almirah, behind the shelf, in the meter room or any other such corner.

19.  Name the materials used by a crow to make its nest.

Ans: A crow uses all types of material, like wires and small wooden pieces, to make its nest.

20.  Where does the crow build its nest?

Ans: The crow builds its nest on, or near, the topmost branches of a tree.

21.  How does a tailor bird make its nest?

Ans: i) A tailor bird stitches the leaves with the help of its beak using small twigs as thread to make its nest.

ii) It uses straws, soft twigs and feathers, inside the nest, to make a cushion.

22.  Which bird makes a tuk-tuk sound, while making its nest in a tree trunk?

Ans: A barbet or a coppersmith, makes tuk-tuk sound, while making its nest in a tree trunk.

23.  When, and where, does a barbet make its nest?

Ans: In summers, a barbet makes its nest in the holes of tree trunk.

24.  Name the materials used by the sunbird to make its nest.

Ans: The sunbird uses plant fibres, grass, spiderweb and feathers for making its nests.

25.  How the nesting habit of weaver bird is different from other birds?

Ans: i) In case of weaver birds, it is the male who weaves the nest.

ii) The male bird weaves the nest beautifully in different shapes.

iii) The female bird chooses a nest where she feels most comfortable.

26.  Name the materials used by penguins to make their nest.

Ans: Penguins make their nest by using stones and pebbles.

27.  Why the penguin uses stones and pebbles to make its nest?

Ans:i) Penguins live in very cold places.

ii) It is difficult to find twigs, grass, or straw in such places.

iii) So, the penguins collect stones and pebbles to make their nests.  

28.  Name the bird who sings sweetly.

Ans: Koel sings sweetly.

29.  Name the bird which does not make its nest.

Ans: Koel does not make its nest.

30.  Where does the koel lay its egg?

Ans: The koel lays its eggs in the crow’s nest.

31.  What happens to the eggs laid by the koel in the crow’s nest?

Ans: The crow hatches the koel’s eggs along with its own eggs.

32.  “The birds have a challenging job.”- Justify this statement.

Ans:i) At times, some animals like cats, rats and other large birds break the nest of the bird.

ii) Thus, the birds have a challenging job to protect their eggs and young ones.

33.  Why we should not break the nests of birds?

Ans: i) Making a nest is a time-consuming task.

ii) Also, the birds have a challenging job to protect their eggs and young ones from enemies and weather. So, we should not break the nests of birds.

34.  What do you mean by migration?

Ans: Moving from one place to another is called as migration.

35.  Describe the causes of migration of birds. (OR)  Why do birds migrate?

Ans: Birds migrate from one place to another,

i)         To search food

ii)       To protect themselves from extreme cold.

iii)     To escape their enemies.

36.  Name some migratory birds.  (OR) Name the birds who migrate to India during winters.

Ans: Siberian crane, painted stork, flamingo, rosypelican, migrate to India during winters.

37.  When do the migratory birds return to their cooler homes?

Ans: The migratory birds return to their cooler homes when summer starts.

38.  Name the bird who travels a distance of 1,76,000 kilometres, from the Arctic region to the Antarctic region.

Ans: The arctic tern

39.  Name region which is the natural home of the Arctic tern.

Ans: The Arctic region is the natural home of the Arctic tern.

STD-5, CHAPTER- 9:FUELS, EXTRA QUESTION ANSWERS

1.      What is a fuel?

Ans: A substance that produces energy on burning is called a fuel.

2.      State the main function of a fuel.

Ans: The main function of a fuel is to produce energy on burning.

3.      Name the types of fuel.

Ans: Fuels are available in solid, liquid or gaseous forms.

4.      Give some examples of solid fuels.

Ans: Wood, coal, coke and cowdung are some examples of solid fuels.

5.      Give some examples of liquid fuels.

Ans: Kerosene, petrol and diesel are some examples of liquid fuels.

6.      Name some gaseous fuels.

Ans: LPG, CNG, PNG and biogas are examples of gaseous fuels.

7.      LPG stands for _______.

Ans: Liquefied petroleum Gas

8.      CNG stands for _______.

Ans: Compressed Natural Gas

9.      PNG stands for ______.

Ans: Piped Natural Gas

10.  Why do we need energy?

Ans: We need energy for cooking, for movement of trains, automobiles and aeroplanes, for generating electricity, for running various machines and so on.

11.  Name some domestic fuels.

Ans: Wood, cowdung cakes, coal, kerosene, LPG, PNG and biogas are some domestic fuels.

12.   Why is biogas regarded as a better fuel than cowdung cakes?

Ans: i) Cowdung cakes produce smoke whose concentration can be as much as five times higher than that produced by ordinary coal.

ii) Biogas, on the other hand, does not produce smoke and are more efficient. They are eco-friendly. Thus, they are regarded as a better fuel than cowdung cakes.

13.  How can we use the ash, obtained by burning coal?

Ans: The ash, a by-product of coal combustion, is used as a filler for things like the tennis rackets and golf balls.

14.  Name some cleaner fuels. Why are they named so?

Ans: i) LPG, CNG, PNG and biogas are cleaner fuels.

ii) They are named so, because they do not produce smoke on burning and do not leave any ash after burning.

15.  How the modern trains different from earlier trains?

Ans:i) Earlier, trains were run with the help of steam engines. In these engines, steam was produced by burning coal.

ii) Now-a-days, train engines use either electricity or diesel.

16.  Vehicles, like buses, cars and scooters run on ______.

Ans: Petrol or diesel

17.  Aeroplanes commonly use a highly refined kerosene based fuel known as _____.

Ans: Aviation Turbine Fuel (ATF).

18.  Why is CNG called a better green fuel?

Ans:i) CNG do not produce smoke on burning and do not leave any ash after burning.

ii) CNG powered vehicles have lower maintenance costs and better efficiency.

iii) It causes less air pollution, is more eco-friendly and causes less harm to the health of humans and animals.

Therefore, CNG is called a better green fuel.

19.  How is coal used by powerhouses for generating electricity?

Ans:i) Powerhouses often burn coal to convert water into steam.

ii) This steam energy is used to operate turbines which in turn, help to generate electricity.

20.  What are the modern methods of producing electricity/

Ans: Electricity is now being produced by using the energy stored in water and also by using wind energy and energy of the sun.

21.  Petrol, diesel and kerosene are all obtained by refining _______.

Ans: Crude oil (petroleum)

22.   What are fossil fuels?

Ans: Fuels which are formed from decomposition of living things over a period of millions of years.

23.  Name the three main fossil fuels.

Ans: Coal, crude oil (petroleum) and natural gases are the three main fossil fuels.

24.  How have fossil fuels been formed?

Ans: i) Fossil fuels are formed by decomposition of animal and plant matter, buried deep under the surface of earth, at high temperature and pressure prevailing there.

ii) Over a period of millions of years, these animal and plant matter got changed into fossil fuels.

25.  Describe the three main fossil fuels.

Ans: The three main natural fossil fuels are, coal, crude oil (petroleum) and natural gas.

i) Coal- It is a combustible black sedimentary rock. It is primarily used for production of heat and electricity.

ii) Crude oil (petroleum) – This was formed from dead sea-creatures. These dead sea-creatures fell to the sea-bed where their bodies underwent chemical changes due to bacteria.

iii) Natural Gas- This was formed in the same way as crude oil. It is often collected when drilling for oil.

26.  When is a source of energy said to be a renewable source of energy? Give some examples of such sources.

Ans: The sources of energy which is freely available and which can be readily replenished, are said to be a renewable source of energy. Examples of renewable sources of energy are, Solar energy, tidal energy, wind and biomass.

27.  Define biomass.

Ans: The waste matter of animals and plants are called biomass.

28.  When a source of energy said to be a non-renewable source of energy? Give two examples of such sources.

Ans: Sources of energy, which once used, cannot be readily replenished are called non-renewable sources of energy.

ii) Coal and petroleum are two of the non-renewable sources of energy.

29.  Define Hydroelectricity.

Ans: Electricity, generated by using the energy of water, is called hydroelectricity.

30.  State two disadvantages of fossil fuels.

Ans: i) Fossil fuels are non-renewable sources of energy.

ii) They are also a major cause of environmental pollution.

31.  Why should efforts need to be made to reduce the use of fossil fuels?

Ans: i) Fossil fuels are available in limited quantity and are not likely to last for a long time.

ii) They are also a major cause of environmental pollution.

We should, therefore, make efforts to reduce the use of fossil fuels.

STD-3, CHAPTER-5: ANIMALS, EXERCISE QUESTION ANSWERS

 A.     FILL IN THE BLANKS.

1.      Land animals generally walk on ______ legs.

Ans: four

2.      Desert animals can tolerate _______ temperatures.

Ans: high

3.      Penguin is found in _______ covered regions.

Ans: snow

4.      Piranha is found in _____ water of lakes and rivers.

Ans: fresh

5.      Orangutan does not like to interact with _______.

Ans: humans

6.      Terrestrial animals live on ______.

Ans: land

B.      MATCH THE FOLLOWING:

1.      dog                                  a. crawls on the ground

2.      camel                              b. people often keep it as a pet.

3.      snake                              c. can live without water for many days

4.      toad                                d. has thick fur on its body

5.      polar bear                      e. lives both on land and in water

      Ans:

1.      dog                               b. people often keep it as a pet

2.      camel                           c. can live without water for many days

3.      snake                           a. crawls on the ground

4.      toad                             e. lives both on land and in water

5.      polar bear                  d. has thick fur on its body

 

C.      TICK THE CORRECT OPTION.

 

1.      This animal lives in a desert -

(a)   tiger        (b) lion          (c) camel        (d) dog

      Ans: camel

2.      An animal, that lives in very cold regions, is the –

(a)   penguin          (b)  snake       (c) zebra          (d) parrot

      Ans: penguin

3.      An animal, that lives in a burrow, is a –

(a)   fish       (b)  giraffe       (c) penguin       (d) snake

       Ans: snake

4.      Nature protects polar bears from cold, by providing them with –

(a)   Webbed feet       (b)  beak       (c) fur       (d) gills

       Ans: fur

5.      It is not an aquatic animal–

(a)   fish          (b) turtle        (c) rabbit          (d) starfish

      Ans: rabbit

D.     ANSWER THE FOLLOWING QUESTIONS IN BRIEF.

 

1.      Name any four land animals.

Ans: Horse, cow, dog, cat, are four land animals.

2.      Name any two things that forests provide to animals.

Ans: Forests provide food and shelter to animals.

3.      How do fins and gills help a fish?

Ans: Fins help a fish to swim and gills help it to breathe.

4.      Why do frogs need water?

Ans: Frogs need water for laying their eggs.

5.      Why dogs and cats are favourite pets of many people?

Ans: i) Dogs and cats like to interact and play with humans.

ii) They can learn the tricks and can play games.

iii) They also love their masters.

So, dogs and cats are favourite pets of many people.

E.      ANSWER THE FOLLOWING QUESTIONS.

 

1.      State the special features which help a camel to live in a desert.

Ans: i) Camels can tolerate high temperatures.

ii) Camels can store water and food in their bodies.

iii) Camels have padded feet that help them to walk on sand.

2.      How do skin colours and body patterns of some animals help to save them from danger?

Ans: i) The colour of the skin and body patterns of some animals, help them to merge with their surroundings so that their enemies cannot see them.

ii) Thus the skin colours and body patterns of some animals help to save them from danger.

3.      Why are dolphins considered to be intelligent animals?

Ans: i) Dolphins can easily learn to perform tricks and play games.

ii) So, dolphins are considered to be intelligent animals.

STD-3, CHAPTER-6: FEEDING HABITS OF ANIMALS, EXERCISE QUESTION ANSWERS

 A.     FILL IN THE BLANKS.

1.      Snakes ________ their prey.

Ans: Swallow

2.      Giraffe feeds on ­­­_______ only.

Ans: plants

3.      Frog has a _______ tongue.

Ans: sticky

4.      Buffaloes ________ their food first and then chew it.

Ans: nibble

5.      Butterfly _______ its food.

Ans: sucks

6.      Squirrel has sharp front _______ like teeth.

Ans: chisel

B.      MATCH THE FOLLOWING:

1.      snake                                  a. sugarcane

2.      monkey                              b. frog

3.      lion                                     c. banana

4.      elephant                            d. deer

      Ans:

1.      snake                               b. frog

2.      monkey                           c. banana

3.      lion                                  d. Deer

4.      elephant                         a. sugarcane

 

C.      TICK THE CORRECT OPTION.

 

1.      The animal, that eats both plants and animals, is the -

(a)   tiger        (b) cow          (c) rat        (d) horse

      Ans: rat

2.      Dog tears the flesh with –

(a)   Chisel teeth          (b) grinding teeth         (c) pointed teeth          (d) tube

      Ans: pointed teeth

3.      Poultry birds should be fed with–

(a)   Green grass       (b)  fresh fruits       (c) milk       (d) grains

       Ans: grains

4.      It is a herbivorous animal–

(b)   fox          (b) cow        (c) rat          (d) snake

      Ans: cow

D.     ANSWER THE FOLLOWING QUESTIONS IN BRIEF.

 

1.      What are carnivorous animals?

Ans: Flesh eating animals are called carnivorous animals.

2.      Name the kind of teeth that help a cow to chew the grass.

Ans: Strong and broad back teeth, help a cow to chew the grass.

3.      Name two animals which gnaw their food.

Ans: Two animals which gnaw their food are, rabbit and rat.

4.      Name the type of teeth that squirrels have. Name two more animals having the same type of teeth.

Ans: Squirrels have sharp pointed chisel like teeth. Two more animals having the same type of teeth are, rabbit and rat.

E.      ANSWER THE FOLLOWING QUESTIONS.

 

1.      State one difference between herbivorous and omnivorous animals. Give one example of each type.

Ans: i) Herbivorous animals only eat plant products. Omnivorous animals eat both plant and animal products.

ii) Cow is a herbivorous animal and dog is an omnivorous animal.

2.      How does a lizard take its food?

Ans: i) A lizard catches its prey with the help of its sticky tongue.

ii) Lizards swallow their food without biting ir chewing the food.

3.      Explain the term ‘chewing the cud’?

Ans: i) Grass eating animals first nibble their food and put it inside their bodies.

ii) When they relax, they bring back part of the food into their mouths and then chew it properly. This is called ‘chewing the cud’.

4.      Write any two ways that can help us in taking care of domestic animals.

Ans: Two ways that can help us in taking care of domestic animals are as follows,

i) Poultry birds, like hen and duck, should be fed with grains and water.

ii) The shelter of all domestic animals should be clean, dry, and airy.

5.      How do butterfly and mosquito have their food?

Ans: Butterfly and mosquitoes, have a long hollow tube like structure. This helps them to suck their food.