Available Answers

1. 1.

   Choose the correct answer:

   1. Global warming is caused due to the presence of excess of this gas in the atmosphere.
      1. Oxygen
      2. Carbon dioxide
      3. Nitrogen
      4. Carbon monoxide
   2. The gas released during respiration is
      1. oxygen
      2. carbon dioxide
      3. nitrogen dioxide
      4. sulphur dioxide
   3. Burning of fuel produces 
      1. carbon dioxide
      2. sulphur dioxide
      3. both of a and b
      4. none of these
   4. A gas which supports combustion is
      1. nitrogen
      2. oxygen
      3. hydrogen
      4. methane
   5. The process of photosynthesis requires
      1. oxygen gas
      2. carbon dioxide gas
      3. nitrogen gas
      4. all of these
2. 2.

   Fill in the blanks:

   1. Boats, gliders and parachutes use _________________ for their movement.
   2. Air exert _________________ equally in all directions due to the random motion of its molecules.
   3. _________________ is used in fire extinguishers.
   4. When moist air comes in contact with a cold surface, the _________________ present in the air condenses on the cooler surface.
   5. _________________ released from the burning of fossil fuels cause headache, irritation in the respiratory tract and suffocation.
3. 3.

   Match the following:

   Column A	Column B
   1. Nitrogen	a. For artificial respiration
   2. Carbon dioxide	b. Run on tyres inflated with air
   3. Oxygen cylinders	c. Photosynthesis
   4. Vehicles	d. Protein formation
   5. Ozone	e. Rusting
   6. Moist air	f. Prevents ultraviolet radiation

    

4. 4.

   Name the main active and inactive components of air.
5. 5.

   Write the composition of air by volume.
6. 6.

   Define humidity.