Exercises
concentration of CO2?
5. Tick the correct answer:
fi) lungs
i spiracles
(ii) gills
(iv) skin
1 Why does an athlete breathe faster and deeper than usual at
2. List the similarities and differences betwen aerobic and anaerskole
3. Why do we often sneeze when we inhale a lot of dust-laden air?
4. Take three test-tubes. Fill 4th of each with water. Label them A, Band
C. Keep a snail in test-tube A, a water plant in test-tube Band in C.
keep snail and plant both. Which test-tube would have the highest
la) In cockroaches, air enters the body through
Answers
Answer:
Question 1:
Why does an athlete breathe faster and deeper than usual after finishing the race?
Answer:
When the athlete runs in the race, his body needs more energy. In order to get extra energy, the athlete breathes faster, because more oxygen is supplied to our cells.
It speeds up the breakdown of food and more energy is released.
After finishing the race, all energy that was getting used in race is now free. So, all the cells taking more oxygen is normal now.
Question 2:
List the similarities and differences between aerobic and anaerobic respiration.
Answer:
Similarities:
Food is oxidized in both cases and energy is released.
Differences:
Aerobic respiration takes place in presence of oxygen; whereas anaerobic respiration takes place in absence of oxygen.
Carbon dioxide and water are the end products of aerobic respiration, while alcohol is the end product of anaerobic respiration.
Aerobic respiration releases more energy than anaerobic respiration.
Question 3:
Why do we often sneeze when we inhale a lot of dust-laden air?
Answer:
When dust particles enter our nostril, it triggers a message to the brain. The brain instructs the nasal chamber to initiate sneezing.
This is a method to remove the unwanted dust particles from the nostrils. Sneezing is a type of defence mechanism used by our body. Other defence mechanism is cough.