Available Answers

1. 1.

   Rewrite the following statements correctly.

   1. The contamination of air with desirable materials is called air pollution.
   2. In the process of distillation, chlorine tables are added to the container with water.
   3. The micro-organisms present in the soil make it infertile and disturb in maintaining the eco system.
   4. Eclipses occur when the sun, the earth and the moon are at right angles with each other.
   5. Sputnik-1 was the first satellite launched by India.
2. 2.

   Give one word for the following.

   1. Structure build along river banks to prevent soil erosion by flooding.
   2. The outermost layer of the atmosphere.
   3. Purification of water first by evaporation and then condensation.
   4. Farming in the hilly area in which the slope is cut into steps.
   5. Man-made objects that are sent into space to orbit the earth.
3. 3.

   Match the following columns.

   Column A	Column B
   1. Amount of water vapour present in air	a. tides
   2. Removal of insoluble impurities from water	b. deforestation
   3. Indiscriminate cutting of trees	c. humidity
   4. Weather forecasting and cyclone warnings	d. sedimentation
   5. Gravity of moon	e. weather satellite

    

4. 4.

   Solve the following crossword with the help of clues given below.

   Across

   1. The process by which soil is formed.
   3. It reduces soil erosion.
   8. A simple way to remove soluble impurities from water.

   Down

   2. These occur due to the revolution of the earth and the moon.
   4. These are caused due to the gravity oof moon.
   5. The major component of air, used by plants
   6. Changing shapes of the moon.
   7. Nearest neighbour of the earth in space and its natural satellite also.