Available Answers

1. 1.

   Why do we breathe fast after running for a few minutes?

2. 2.

   Why do we feel hungry after a physical activity?

3. 3.

   Do all fishes have lungs? Why do whales and dolphins come up to the water surface and release a fountain of water?

4. 4.

   Check point:

   1. During heavy exercise, we get cramps in the legs because of the accumulation of _______________.
      1. Lactic acid
      2. Water
      3. Alcohol
      4. Carbon dioxide
   2. Cockroaches have _______________ for breathing.
      1. Gills
      2. Skin
      3. Lungs
      4. Spiracles
   3. Which organ is not associated with respiration?
      1. Lungs
      2. Pharynx
      3. Gills
      4. Trachea
   4. Breakdown of food in the cell with release of energy _______________.
      1. Respiration
      2. Transpiration
      3. External respiration
      4. Internal respiration
   5. Which of the following respires only anaerobically?
      1. Cockroach
      2. Fungi
      3. Yeast
      4. All bacteria
5. 5.

   True-False:

   1. Plants absorb water through stomata.
   2. During heavy exercise, the breathing rate of a person slows down.
   3. Frogs breathe through their skin as well as through their lungs.
   4. Earthworms breathe through their skin.
   5. The air we breathe out is rich in carbon dioxide.
   6. Fishes have gills for respiration.
6. 6.

   Fill in the blanks:

   1. End products of aerobic respiration are ________________, ________________ and energy.
   2. Chest increases in size during ________________ and decreases during ________________.
   3. During inhalation, ribs move ________________ and ________________ moves down.
   4. Carbon dioxide turns ________________ milky.
   5. Exhaled air has ________________ % of carbon dioxide and ________________ % of oxygen.
   6. Aquatic animals breathe through ________________.
   7. Anaerobic respiration occurs in the ________________ of oxygen.