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Quiz Chapter 2: Respiration

10 questions · Form 3 Science Bab 2: Respiration

10 questions · plays in fullscreen

Full Question List & Answer Key

Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.

1. Which component of tobacco smoke is a sticky black substance known to cause lung cancer?

  1. Nicotine
  2. Carbon monoxide
  3. Cigarette tar
  4. Sulfur dioxide
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Answer: C

Cigarette tar is a viscous carcinogen that deposits in the lungs, paralyzes cilia, and causes cell mutations leading to cancer.

2. In the human respiratory system, what is the main function of cilia and mucus in the nasal cavity and trachea?

  1. To absorb oxygen directly into blood vessels
  2. To trap dust particles and micro-organisms and sweep them away from lungs
  3. To cool down incoming atmospheric air
  4. To produce carbon dioxide for exhalation
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Answer: B

Mucus traps foreign dirt and pathogens, while microscopic hair-like cilia sweep the trapped debris up toward the pharynx.

3. What physiological effect occurs when sulfur dioxide and nitrogen dioxide gases enter human air passages?

  1. They dissolve in blood plasma and increase oxygen transport
  2. They irritate and cause inflammation of the respiratory tract lining
  3. They cause immediate destruction of lung cilia without coughing
  4. They turn red blood cells into white blood cells
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Answer: B

Sulfur dioxide and nitrogen dioxide are acidic gas pollutants that irritate air passages, triggering coughing, asthma, and bronchitis.

4. Carbon monoxide in cigarette smoke is dangerous because it:

  1. Destroys the cilia lining the trachea
  2. Binds tightly to hemoglobin, reducing oxygen transport in the blood
  3. Causes uncontrolled division of lung cells
  4. Forms an acidic solution that corrodes bronchial walls
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Answer: B

Carbon monoxide competes with oxygen by binding strongly to hemoglobin to form carboxyhemoglobin, severely reducing oxygen-carrying capacity.

5. What is the correct pathway taken by air through the human respiratory tract during inhalation?

  1. Nasal cavity -> Pharynx -> Larynx -> Trachea -> Bronchus -> Bronchiole -> Alveolus
  2. Nasal cavity -> Larynx -> Pharynx -> Bronchus -> Trachea -> Bronchiole -> Alveolus
  3. Pharynx -> Nasal cavity -> Trachea -> Larynx -> Bronchiole -> Bronchus -> Alveolus
  4. Nasal cavity -> Trachea -> Pharynx -> Larynx -> Bronchiole -> Bronchus -> Alveolus
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Answer: A

Air travels in order through the nasal cavity, pharynx, larynx, trachea, primary bronchi, bronchioles, and finally reaches the alveoli.

6. An adult frog can perform gas exchange through its skin when submerged in moist soil. What feature allows its skin to be effective for gas exchange?

  1. Presence of thick chitinous scales
  2. Thin, moist skin richly supplied with blood capillaries underneath
  3. Specialized spiracles embedded along the outer dermis
  4. Large surface area covered by gill filaments
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Answer: B

A frog's skin is thin, kept constantly moist by mucus secretions, and well-supplied with blood capillaries for rapid diffusion.

7. By which process does gas exchange occur across the walls of alveoli and blood capillaries?

  1. Active transport
  2. Osmosis
  3. Diffusion
  4. Transpiration
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Answer: C

Gaseous exchange takes place passively by diffusion down a partial pressure gradient.

8. Which change occurs during human inhalation?

  1. The intercostal muscles relax and the ribcage moves downwards
  2. The diaphragm muscle contracts and flattens
  3. The volume of the thoracic cavity decreases
  4. The air pressure in the thoracic cavity increases above atmospheric pressure
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Answer: B

During inhalation, the diaphragm contracts and flattens, while intercostal muscles contract to lift the ribcage, expanding cavity volume.

9. Which respiratory condition is characterized by the breakdown and loss of elasticity of alveolar walls, leading to reduced surface area for gas exchange?

  1. Emphysema
  2. Asthma
  3. Bronchitis
  4. Lung cancer
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Answer: A

Emphysema is a chronic lung disease, usually caused by long-term smoking, where alveolar walls are permanently destroyed.

10. What happens to the pressure inside the human thoracic cavity during exhalation?

  1. It decreases below atmospheric pressure
  2. It increases above atmospheric pressure
  3. It drops to zero
  4. It remains exactly equal to atmospheric pressure at all times
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Answer: B

Exhalation reduces thoracic volume, compressing air inside so its pressure rises above atmospheric pressure, driving air out.

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