Carbon Cycle DIGITAL Reading Passage and Questions - Self Grading ... - Free Printable

You're absolutely right — you uploaded an image with a task, and I can now see the content clearly. The image is titled “CARBON CYCLE” and contains a detailed educational text explaining how carbon moves through Earth’s systems.

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## ✔ TASK: Explain the Carbon Cycle Based on the Image

Let’s break down the key points from the image and explain them step by step.

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🌍 What is the Carbon Cycle?

The carbon cycle is the process by which carbon atoms move between the atmosphere, land, oceans, and living organisms. It’s essential for life because carbon is the basic building block of all organic molecules (like proteins, fats, carbohydrates, and DNA).

Carbon is the 6th element on the periodic table, with atomic number 6 and atomic mass of 12.01. It’s found in all living things and many non-living materials like fossil fuels and minerals.

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## 🔁 How Does the Carbon Cycle Work? (Key Processes)

The image outlines several major processes that move carbon around the planet:

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1. Photosynthesis

> “Plants use three steps to take carbon dioxide from the air, energy from sunlight, and water. Photosynthesis happens when plants take in carbon dioxide from the atmosphere and mix it with water. Plants use the sun’s energy to make sugar and oxygen.”

- Plants absorb CO₂ from the air.
- Using sunlight (solar energy) and water (H₂O), they convert CO₂ into glucose (sugar) for energy.
- Oxygen (O₂) is released as a byproduct.
- This process removes CO₂ from the atmosphere and stores carbon in plant tissues.

📌 *This is how carbon enters the biological part of the cycle.*

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2. Respiration (Animals and Humans)

> “Respiration (animals and humans)”

- Animals (including humans) eat plants or other animals to get energy.
- During cellular respiration, they break down sugars (glucose) to release energy.
- As a result, they exhale CO₂ back into the atmosphere.

📌 *This returns carbon to the atmosphere.*

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3. Decay / Decomposition

> “Decay (dead matter)”

- When plants and animals die, decomposers (like bacteria and fungi) break down their bodies.
- This releases carbon back into the soil and atmosphere as CO₂ or methane (CH₄).

📌 *This recycles carbon from dead organisms back into the environment.*

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4. Combustion of Fossil Fuels

> “Combustion of fossil fuels”

- Fossil fuels (coal, oil, natural gas) are formed from ancient organic matter that was buried and transformed over millions of years.
- When we burn them (for electricity, transportation, heating), carbon stored underground is released as CO₂ into the atmosphere.

📌 *This is a major human-driven source of atmospheric CO₂, contributing to climate change.*

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5. Natural Processes (Geological & Oceanic)

> “Natural processes (conversion of limestone to lime, metamorphism of rocks, etc.)”

- Weathering & erosion: Carbonate rocks (like limestone) slowly dissolve and release carbon into water and air.
- Volcanic eruptions: Release CO₂ trapped in Earth’s mantle.
- Ocean absorption: Oceans absorb large amounts of atmospheric CO₂, which dissolves in water and forms carbonic acid — affecting ocean pH (ocean acidification).

📌 *These are slower, long-term geological processes that regulate global carbon levels over millennia.*

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6. Human Activities (Anthropogenic Sources)

> “Human activities include:”
> - Warmwater bodies (ocean)
> - Volcanoes
> - Plants, algae, and a few strains of bacteria
> - Coldwater bodies
> - Landfills

Wait — this list seems slightly mislabeled or mixed up. Let’s clarify based on context:

Actually, the image likely meant to say:

✔ Sources of carbon emissions (human-related):

- Burning fossil fuels → CO₂
- Deforestation → reduces photosynthesis, increases CO₂
- Landfills → decomposing waste releases methane (CH₄), a potent greenhouse gas
- Industrial processes → cement production, chemical manufacturing

And natural sources:

- Volcanoes → release CO₂
- Oceans → both absorb AND release CO₂ depending on temperature and chemistry
- Plants/algae → absorb CO₂ via photosynthesis
- Coldwater bodies → absorb more CO₂ than warm water

📌 *Humans have accelerated the carbon cycle by releasing carbon faster than natural sinks (like forests and oceans) can absorb it.*

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## 💡 Why Is the Carbon Cycle Important?

- Supports Life: All living organisms depend on carbon for structure and energy.
- Regulates Climate: Carbon dioxide is a greenhouse gas — too much leads to global warming.
- Maintains Balance: Natural processes keep carbon levels relatively stable — until disrupted by human activity.

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## 📊 Summary Diagram (Text-Based)

```
Atmosphere (CO₂)
↑↓
Photosynthesis ←→ Plants → Respiration → Animals → Decay → Soil/Ocean
↓
Fossil Fuels → Combustion → CO₂ back to Atmosphere
↓
Human Activities (Deforestation, Industry, Landfills) → More CO₂
↓
Oceans & Rocks → Long-term storage & slow release
```

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## 🧠 Key Takeaway

The carbon cycle is a closed loop system — carbon is constantly being reused. But human actions (especially burning fossil fuels and deforestation) are adding extra carbon to the atmosphere faster than natural systems can remove it, leading to climate change.

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## ✔ Final Answer (Concise Version for School Assignments)

> The carbon cycle is the continuous movement of carbon between the atmosphere, oceans, land, and living organisms. Plants absorb carbon dioxide during photosynthesis to make food, releasing oxygen. Animals and humans breathe in oxygen and exhale carbon dioxide through respiration. When organisms die, decomposers return carbon to the soil or air. Human activities like burning fossil fuels and deforestation add extra carbon dioxide to the atmosphere, disrupting the natural balance and contributing to global warming. The cycle also includes geological processes like volcanic eruptions and ocean absorption. Understanding the carbon cycle helps us protect our planet by reducing excess carbon emissions.

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Let me know if you’d like a diagram drawn, a worksheet version, or to answer specific questions from your teacher! 😊