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Photosynthesis is a crucial process in the carbon cycle. It occurs in green plants, algae, and some bacteria. During photosynthesis, these organisms take in carbon dioxide (CO鈧�) from the atmosphere and water (H鈧侽) from the soil. Using sunlight as an energy source, they convert these into glucose (C鈧咹鈧佲倐O鈧�) and oxygen (O鈧�). This can be represented by the equation:

6CO鈧� + 6H鈧侽 + light energy 鈫� C鈧咹鈧佲倐O鈧� + 6O鈧�

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This process is vital as it removes CO鈧� from the atmosphere and provides oxygen for living organisms to breathe. Photosynthesis not only sustains plant life but also supports the entire food web, as plants are primary producers.

Key points about photosynthesis:

• Removes CO鈧� from the atmosphere.
• Produces glucose and oxygen.
• Fundamental for plant growth and energy production.

Respiration is another fundamental process in the carbon cycle. It occurs in nearly all living organisms, including plants, animals, fungi, and many microorganisms. During respiration, glucose (C鈧咹鈧佲倐O鈧�) is broken down with oxygen (O鈧�) to produce carbon dioxide (CO鈧�), water (H鈧侽), and energy. The overall equation is:

 C鈧咹鈧佲倐O鈧� + 6O鈧� 鈫� 6CO鈧� + 6H鈧侽 + energy

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This process essentially reverses photosynthesis. Through respiration, organisms convert the energy stored in glucose into a form that can be used for biological work. The CO鈧� produced is released back into the atmosphere, completing the cycle.

Key points about respiration:

• Releases CO鈧� back into the atmosphere.
• Provides energy for living organisms.
• Occurs in both plants and animals, but also in other organisms.

Decomposition is the process by which dead organic matter breaks down, returning carbon and other essential nutrients to the environment. This is primarily carried out by decomposers like bacteria, fungi, and certain invertebrates. These organisms digest and break down dead plants, animals, and waste products. During decomposition, the carbon in these materials is converted back into carbon dioxide (CO鈧�), which is released into the atmosphere or soil. This can be represented by the simplified equation:

Organic matter + O鈧� 鈫� CO鈧� + nutrients + energy

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Decomposition is essential because it recycles nutrients, making them available for new plant growth. It also ensures that carbon moves through the ecosystem, maintaining the balance of the carbon cycle.

Key points about decomposition:

• Breaks down dead organic matter.
• Releases CO鈧� back into the environment.
• Recycles nutrients for new plant growth.