Available Answers

1. 1.

   Tick (√) the correct options:

   1. Sea/Ocean water cannot be used for domestic purposes because it contains
      1. soluble salts
      2. dust
      3. insoluble salts
      4. acid
   2. How much of the earth's surface is covered with water?
      1. about two-thirds
      2. about three-fourths
      3. about one-fourth
      4. about one-third
2. 2.

   Tick (√) the correct options:

   1. The solid state of water is _______________.
      1. ice
      2. steam
      3. water vapour
      4. none of these
   2. The process of changing water into water vapour is _______________.
      1. evaporation
      2. filtration
      3. condensation
      4. sedimentation
3. 3.

   Tick (√) the correct options:

   1. For which purpose is water needed?
      1. agriculture
      2. industries
      3. transportation
      4. all of these
   2. Coming down of water in the form of rain, hail or snow is called _______________.
      1. evaporation
      2. condensation
      3. precipitation
      4. all of these
   3. Which of the following maintains the supply of water on land?
      1. water table
      2. water cycle
      3. water bodies
      4. none of these
   4. The process by which excess water is released by plants into air as vapour is _______________.
      1. condensation
      2. transpiration
      3. precipitation
      4. all of these
   5. This reduces the visibility near the ground on cold winter mornings.
      1. fog
      2. water vapour
      3. smoke
      4. dust
   6. _______________ pollution reduces water availability.
      1. Land
      2. Air
      3. Noise
      4. Water
4. 4.

   Fill in the blanks:

   1. The _______________ state of water is ice.
   2. Water cycle helps in regulating the _______________ on the earth.
   3. Water regulates our body temperature by the process of _______________.
   4. At greater height, water vapour in air _______________ to form tiny drops of water.
   5. _______________ increases the availability of groundwater.
   6. Floods wash away the top layer of the soil resulting in _______________.
5. 5.

   State whether the following statements are true (T) or false (F). Rewrite the false statements correctly:

   1. Water exists in three states in nature.
   2. There is no shortage of drinking water during floods.
   3. Rainwater harvesting is related to replenishing groundwater.
   4. We see nothing on the outer surface of the glass containing chilled water.
   5. Water vapour enters the earth's atmosphere only through evaporation.
6. 6.

   What is formed on (a) melting of ice (b) freezing of water (c) evaporation of water?