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Quiz Chapter 7: Air

10 questions · Form 1 Science Bab 7: Air

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. What effect does haze have on the surrounding environment?

  1. Increases atmospheric oxygen level
  2. Reduces visibility and causes respiratory difficulties
  3. Prevents soil erosion
  4. Neutralizes acid rain
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Answer: B

Haze consists of suspended fine particulate matter like soot and dust, severely reducing visibility and triggering asthma/respiratory issues.

2. Which biological activity consumes oxygen gas from the air?

  1. Photosynthesis
  2. Respiration
  3. Transpiration
  4. Nitrogen fixation
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Answer: B

Cellular respiration in living organisms consumes oxygen to break down glucose and release energy.

3. Which gas is released back into the atmosphere solely through the process of photosynthesis?

  1. Carbon dioxide
  2. Oxygen
  3. Nitrogen
  4. Water vapor
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Answer: B

Photosynthesis by green plants is the primary biological process that produces and releases oxygen into the air.

4. Which percentage accurately represents the proportion of Oxygen gas in clean dry air?

  1. 78%
  2. 21%
  3. 1%
  4. 0.03%
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Answer: B

Oxygen makes up approximately 21% of clean atmospheric air.

5. Which air pollutant is produced by incomplete combustion of carbon fuels in vehicle exhausts?

  1. Carbon dioxide
  2. Sulfur dioxide
  3. Carbon monoxide
  4. Methane
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Answer: C

Incomplete combustion releases carbon monoxide (CO), a colorless, odorless, toxic gas.

6. Which gas present in air is essential for green plants to undergo photosynthesis?

  1. Oxygen
  2. Nitrogen
  3. Carbon dioxide
  4. Argon
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Answer: C

Green plants absorb carbon dioxide from the air to synthesize glucose during photosynthesis.

7. What is the approximate percentage of Nitrogen present in clean atmospheric air?

  1. 21%
  2. 78%
  3. 0.03%
  4. 0.97%
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Answer: B

Nitrogen forms the largest proportion of clean air at approximately 78% by volume.

8. How does a carbon dioxide fire extinguisher extinguish a flame?

  1. By lowering the temperature of the fuel below its ignition point
  2. By displacing oxygen and cutting off the oxygen supply
  3. By chemically absorbing the fuel source
  4. By increasing atmospheric pressure around the fire
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Answer: B

Carbon dioxide gas is denser than air and non-combustible; it smothers the fire by preventing oxygen from reaching the fuel.

9. Why is carbon monoxide gas extremely dangerous to human health?

  1. It causes skin burns on contact
  2. It combines with hemoglobin in blood, reducing oxygen transport
  3. It destroys human lung tissue instantly
  4. It triggers severe allergic reactions on eyes
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Answer: B

Carbon monoxide binds strongly with hemoglobin to form carboxyhemoglobin, preventing red blood cells from carrying oxygen.

10. Which three elements make up the Fire Triangle required for combustion?

  1. Fuel, Nitrogen, Heat
  2. Fuel, Oxygen, Heat
  3. Carbon dioxide, Oxygen, Fuel
  4. Spark, Fuel, Nitrogen
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Answer: B

Combustion requires three elements simultaneously: Fuel, Oxygen, and Heat.

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