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CodeVID-M7-WS
Respiration in Organisms — Practice Worksheet
Chapter: Respiration in Organisms
Topic: Respiration in Organisms
Maximum Marks: 25
Time: 30 minutes
Name: ____________________ Roll No.: __________ Date: ____________

General Instructions

  • All questions are compulsory.
  • Choose the correct option (A, B, C or D) for each question.
  • The answer key is at the end — try the paper first!
Section A — Multiple Choice (1 mark each) 25 × 1 = 25 marks
1.
The process by which cells break down food to release energy is called:
  • A.Photosynthesis
  • B.Respiration
  • C.Digestion
  • D.Transpiration
2.
Aerobic respiration takes place in the:
  • A.Absence of oxygen
  • B.Presence of oxygen
  • C.Absence of food
  • D.Dark only
3.
Aerobic respiration breaks glucose down into carbon dioxide, energy, and:
  • A.Alcohol
  • B.Water
  • C.Lactic acid
  • D.Starch
4.
Anaerobic respiration in muscles during heavy exercise produces:
  • A.Alcohol
  • B.Lactic acid
  • C.Oxygen
  • D.Glucose
5.
Anaerobic respiration in yeast produces alcohol and:
  • A.Oxygen
  • B.Carbon dioxide
  • C.Water
  • D.Lactic acid
6.
Taking in oxygen-rich air and giving out carbon-dioxide-rich air is called:
  • A.Respiration
  • B.Breathing
  • C.Digestion
  • D.Assimilation
7.
During inhalation, the diaphragm:
  • A.Relaxes and curves up
  • B.Contracts and flattens
  • C.Disappears
  • D.Stays still
8.
One complete breath consists of one inhalation and one:
  • A.Heartbeat
  • B.Exhalation
  • C.Pulse
  • D.Digestion
9.
Compared with inhaled air, exhaled air contains more:
  • A.Oxygen
  • B.Carbon dioxide
  • C.Nitrogen only
  • D.Hydrogen
10.
The breathing rate of a person generally ______ during exercise.
  • A.Decreases
  • B.Increases
  • C.Stays the same
  • D.Becomes zero
11.
The windpipe that carries air towards the lungs is called the:
  • A.Oesophagus
  • B.Trachea
  • C.Bronchiole
  • D.Alveolus
12.
The tiny air sacs in the lungs where gases are exchanged are the:
  • A.Bronchi
  • B.Alveoli
  • C.Nostrils
  • D.Villi
13.
Air is filtered, warmed, and moistened in the:
  • A.Stomach
  • B.Nasal cavity
  • C.Trachea
  • D.Lungs
14.
The trachea divides into two tubes called:
  • A.Alveoli
  • B.Bronchi
  • C.Bronchioles
  • D.Villi
15.
At the alveoli, oxygen passes from the air into the:
  • A.Stomach
  • B.Blood
  • C.Trachea
  • D.Nose
16.
Fish breathe using organs called:
  • A.Lungs
  • B.Gills
  • C.Tracheae
  • D.Spiracles
17.
Insects take in air through tiny openings called:
  • A.Alveoli
  • B.Spiracles
  • C.Nostrils
  • D.Gills
18.
An earthworm breathes through its:
  • A.Lungs
  • B.Gills
  • C.Moist skin
  • D.Tracheae
19.
Which animal can breathe through both its skin and its lungs?
  • A.Fish
  • B.Frog
  • C.Cockroach
  • D.Earthworm
20.
The network of fine air tubes through which insects breathe is the:
  • A.Alveoli
  • B.Tracheae
  • C.Bronchi
  • D.Gills
21.
Plants respire:
  • A.Only during the day
  • B.Only at night
  • C.All the time, day and night
  • D.Never
22.
Leaves of plants exchange gases through tiny pores called:
  • A.Lenticels
  • B.Stomata
  • C.Alveoli
  • D.Spiracles
23.
The small openings in the stems of woody plants used for gas exchange are:
  • A.Stomata
  • B.Lenticels
  • C.Gills
  • D.Tracheae
24.
At night, plants take in oxygen and give out:
  • A.Oxygen
  • B.Carbon dioxide
  • C.Nitrogen
  • D.Glucose
25.
Waterlogged soil can harm plant roots because it lacks:
  • A.Water
  • B.Air (oxygen)
  • C.Minerals
  • D.Sunlight

Answer Key

Section A — Multiple Choice (1 mark each)
  1. (B) Respiration
  2. (B) Presence of oxygen
  3. (B) Water
  4. (B) Lactic acid
  5. (B) Carbon dioxide
  6. (B) Breathing
  7. (B) Contracts and flattens
  8. (B) Exhalation
  9. (B) Carbon dioxide
  10. (B) Increases
  11. (B) Trachea
  12. (B) Alveoli
  13. (B) Nasal cavity
  14. (B) Bronchi
  15. (B) Blood
  16. (B) Gills
  17. (B) Spiracles
  18. (C) Moist skin
  19. (B) Frog
  20. (B) Tracheae
  21. (C) All the time, day and night
  22. (B) Stomata
  23. (B) Lenticels
  24. (B) Carbon dioxide
  25. (B) Air (oxygen)
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