To identify the processes that bring carbon into the atmosphere, let's evaluate the options:
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Burning fossil fuels - This process releases carbon dioxide (CO2) into the atmosphere, so it does bring carbon into the atmosphere.
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Limestone formation - This involves the deposition of calcium carbonate and generally sequesters carbon rather than releasing it, so it does not bring carbon into the atmosphere.
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Respiration - Living organisms, through the process of respiration, consume oxygen and release carbon dioxide, thus bringing carbon into the atmosphere.
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Photosynthesis - This process takes in carbon dioxide from the atmosphere and converts it into glucose, so it does not bring carbon into the atmosphere.
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Equilibrium with the ocean - This refers to the exchange of carbon dioxide between the ocean and the atmosphere. While it can involve both absorption and release of CO2, processes that lead to net carbon release (like ocean warming) can put carbon in the atmosphere.
So, the processes that bring carbon into the atmosphere are:
- Burning fossil fuels
- Respiration
- Equilibrium with the ocean (in terms of certain conditions)
The options would be:
- Burning fossil fuels
- Respiration
- Equilibrium with the ocean (if it's interpreted in the context of carbon release)