Class 7 Science - Chapter Water: A Precious Resource NCERT Solutions | There are ten tubewells in a lane of fif

Make a sketch showing groundwater and water table. Label it.

You have been asked to maintain a garden. How will you minimise the use of water?

Explain how groundwater is recharged?

Explain the factors responsible for the depletion of water table.

Mark ‘T’ if the statement is true and ‘F’ if it is false:

(a) The freshwater stored in the ground is much more than that present in the rivers and lakes of the world. (T/F)
(b) Water shortage is a problem faced only by people living in rural areas. (T/F)
(c) Water from rivers is the only source for irrigation in the fields. (T/F)
(d) Rain is the ultimate source of water. (T/F)

Fill in the blanks with the appropriate answers:

 (a) People obtain groundwater through________ and ________.                                                                                                                                                         (b) Three forms of water are ________, ________ and ________.
 (c) The water bearing layer of the earth is ________.
 (d) The process of water seepage into the ground is called ________.

Choose the correct option. The total water

(i) in the lakes and rivers of the world remains constant.
(ii) under the ground remains constant.
(iii) in the seas and oceans of the world remains constant.
(iv) of the world remains constant.

Which one of the following is not responsbile for water shortage?

(i) Rapid growth of industries
(ii) Increasing population
(iii) Heavy rainfall
(iv) Mismanagement of water resources

State similarities and differences between the laboratory thermometer and the clinical thermometer.

State differences between acids and bases.

Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food

Name the elements that determine the weather of a place.

Fill the missing word in the blank spaces in the following statements:

(a) Wind is——————air.
(b) Winds are generated due to —————— heating on the earth.
(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.
(d) Air moves from a region of ——— pressure to a region of ———.

In addition to the rock particles, the soil contains

(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants

Why does an athlete breathe faster and deeper than usual after finishing the race?

Match structures given in Column I with functions given in Column II.

Column I                           Column II
(i) Stomata                        (a) Absorption of water
(ii) Xylem                           (b) Transpiration
(iii) Root hairs                    (c) Transport of food
(iv) Phloem                        (d) Transport of water
                                          (e) Synthesis of carbohydrates

Fill in the blanks:

(a) Production of new individuals from the vegetative part of parent is called_____________.
(b) A flower may have either male or female reproductive parts. Such a flower is called_____________.
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as _____________.
(d) The fusion of male and female gametes is termed as _____________.
(e) Seed dispersal takes place by means of _____________, _____________ and _____________.

Classify the following as motion along a straight line, circular or oscillatory motion:

(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge.

Name the following:
(i) A parasitic plant with yellow, slender and tubular stem.
(ii) A plant that has both autotrophic and heterotrophic mode of nutrition.
(iii) The pores through which leaves exchange gases.

Look at Fig. 4.13. Mark where the heat is being transferred by conduction, by convection and by radiation.

Distinguish between a parasite and a saprotroph.

When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.

Why is it necessary to excrete waste products?

The mountaineers carry oxygen with them because:

(a) At an altitude of more than 5 km there is no air.
(b) The amount of air available to a person is less than that available on the ground.
(c) The temperature of air is higher than that on the ground.
(d) The pressure of air is higher than that on the ground.

Make sketches of the two stages in the life history of the silk moth which are directly related to the production of silk.

In places of hot climate it is advised that the outer walls of houses be painted white. Explain.

Indicate the type of climate of the following areas:

(a) Jammu and Kashmir: _________________________________
(b) Kerala: ____________________________________________
(c) Rajasthan: __________________________________________
(d) North-east India: _____________________________________

Tick the correct answer:
(a) In cockroaches, air enters the body through
(i) lungs               (ii) gills
(iii) spiracles        (iv) skin

(b) During heavy exercise, we get cramps in the legs due to the accumulation of
(i) carbon dioxide       (ii) lactic acid
(iii) alcohol                 (iv) water

(c) Normal range of breathing rate per minute in an average adult person at rest is:
(i) 9ñ12                 (ii) 15ñ18
(iii) 21ñ24              (iv) 30ñ33

(d) During exhalation, the ribs
(i) move outwards         (ii) move downwards
(iii) move upwards        (iv) do not move at all