Carbon Cycle Earth Spheres

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Carbon cycle and Earth spheres illustration

📖 Reading Passage

The Carbon Cycle and Earth's Four Spheres

Carbon is one of the most important elements on Earth, constantly moving between four main spheres. The atmosphere contains carbon dioxide gas that plants use for photosynthesis. The biosphere includes all living things - plants absorb carbon dioxide and release oxygen, while animals breathe in oxygen and exhale carbon dioxide. The hydrosphere (oceans, rivers, lakes) dissolves carbon dioxide from the atmosphere, and marine organisms use it to build shells. The lithosphere (Earth's crust and rocks) stores carbon in fossil fuels like coal and oil, and in rocks like limestone. When we burn fossil fuels, carbon returns to the atmosphere as carbon dioxide. This continuous movement of carbon between spheres is called the carbon cycle.

🔍 Part 1: Multiple Choice Questions

1. Which sphere contains carbon dioxide gas that plants use for photosynthesis?

Lithosphere

Atmosphere

Hydrosphere

Biosphere

2. What happens when fossil fuels are burned?

Carbon is destroyed forever

Carbon returns to the atmosphere as carbon dioxide

Carbon moves to the hydrosphere

Carbon becomes oxygen

3. Which spheres are involved when marine organisms build shells? (Select all that apply)

Atmosphere

Hydrosphere

Biosphere

Lithosphere

4. The lithosphere stores carbon in:

Ocean water only

Living plants only

Fossil fuels and rocks

The atmosphere only

✏️ Part 2: Short Answer Questions

5. Complete the sentence: During photosynthesis, plants absorb _____________ from the atmosphere and release _____________.

6. Name the four Earth spheres and give one example of how carbon is found in each sphere.

7. Explain how carbon moves from the lithosphere to the atmosphere when humans use fossil fuels.

8. Describe one way that carbon moves from the atmosphere to the biosphere.

9. Draw a simple diagram showing how carbon moves between at least three of the four Earth spheres. Label each sphere and use arrows to show the direction of carbon movement.