Free Collection of The Carbon Cycle Worksheets for Students - Free Printable

Let's go through each question in the worksheet and solve it step by step.

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Q.1 Fill in the blanks with suitable words.

a) Carbon is a chemical element with the symbol _________.
✔ Answer: C
> Explanation: The chemical symbol for carbon is C, derived from its name.

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b) Carbon in the atmosphere is found in the form of _____________________.
✔ Answer: Carbon dioxide (CO₂)
> Explanation: The primary form of carbon in the atmosphere is carbon dioxide (CO₂), which is a gas that plays a key role in the carbon cycle.

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c) _________________ is the exchange of carbon between the land, the oceans, the atmosphere and the Earth's interior.
✔ Answer: The carbon cycle
> Explanation: The carbon cycle describes how carbon moves through different reservoirs on Earth — atmosphere, oceans, living organisms, soil, and Earth’s crust.

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Q.2 Write T or True if the statement is true; write F or False if the statement is false.

1. All living things are made up of molecules that contain carbon.
✔ Answer: T (True)
> Explanation: Carbon is the backbone of organic molecules (like proteins, carbohydrates, lipids, and nucleic acids), so all living organisms contain carbon-based compounds.

2. Carbon is the most abundant element in the universe.
✘ Answer: F (False)
> Explanation: The most abundant element in the universe is hydrogen, followed by helium. Carbon is abundant but not the most abundant.

3. The burning of fossil fuels releases more carbon dioxide into the atmosphere.
✔ Answer: T (True)
> Explanation: Burning fossil fuels (coal, oil, natural gas) releases stored carbon as CO₂ into the atmosphere, contributing to climate change.

4. Producers capture the carbon dioxide and convert it to glucose through the process of respiration.
✘ Answer: F (False)
> Explanation: Producers (like plants) use photosynthesis, not respiration, to convert CO₂ and water into glucose using sunlight. Respiration is when organisms break down glucose to release energy, producing CO₂.

5. Atmospheric carbon dioxide produces greenhouse effect by trapping heat near Earth's surface.
✔ Answer: T (True)
> Explanation: CO₂ is a greenhouse gas that absorbs infrared radiation and traps heat in the atmosphere, leading to the greenhouse effect.

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Q.3 Label the diagram below which shows the carbon cycle.

Let’s analyze the diagram:

- Sun → provides energy for photosynthesis.
- Tree (plant) → performs photosynthesis.
- Animal (cow) → consumes plant, breathes out CO₂.
- Factory and car → burn fossil fuels, releasing CO₂.
- Decay organisms → decompose dead matter.
- Fossil fuels → formed from buried dead organisms over millions of years.

Now label the boxes:

1. Box above the tree (connected to sun and CO₂):
✔ Photosynthesis
> Plants take in CO₂ and use sunlight to make glucose.

2. Box connected to cow and pointing to CO₂:
✔ Respiration
> Animals release CO₂ during cellular respiration.

3. Box connected to factory/car and pointing to CO₂:
✔ Combustion
> Burning fossil fuels releases CO₂.

4. Box connected to dead organisms and pointing to fossil fuels:
✔ Decomposition
> Decomposers break down dead matter, releasing CO₂ and forming fossil fuels over time.

So the labeled boxes are:

- Top left box (above tree): Photosynthesis
- Middle right box (from animal): Respiration
- Right top box (from factory): Combustion
- Bottom center box (from dead organisms): Decomposition

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Q.4 Carbon dioxide is produced by the human body through _____________.

Options:
a) combustion
b) respiration
c) photosynthesis
d) decomposition

✔ Answer: b) respiration
> Explanation: Humans produce CO₂ as a waste product during cellular respiration, where glucose is broken down to release energy. This occurs in cells, not combustion (which is external burning), photosynthesis (plants only), or decomposition (microbes breaking down dead matter).

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Q.5 Carbon dioxide from livings is also returned to the atmosphere through processes of _____________ of dead tissue.

Options:
a) combustion
b) respiration
c) photosynthesis
d) decomposition

✔ Answer: d) decomposition
> Explanation: When organisms die, decomposers (like bacteria and fungi) break down their tissues, releasing CO₂ back into the atmosphere. This is called decomposition. Combustion can happen later if fossil fuels are burned, but for dead tissue directly, it's decomposition.

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✔ Final Answers Summary:

#### Q.1
a) C
b) Carbon dioxide (CO₂)
c) The carbon cycle

#### Q.2
1. T
2. F
3. T
4. F
5. T

#### Q.3 Diagram Labels
- Top left box: Photosynthesis
- Middle right box: Respiration
- Right top box: Combustion
- Bottom center box: Decomposition

#### Q.4
b) respiration

#### Q.5
d) decomposition

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