Assertion: In nature, the recycling of carbon is essentially a self-regulating feedback system.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that "In nature, the recycling of carbon is essentially a self-regulating feedback system." This means that the processes involved in the carbon cycle work together to maintain a balance in the ecosystem.

2. **Identifying the Components of the Carbon Cycle**: The carbon cycle involves various components including the atmosphere (air), lithosphere (earth), biosphere (living organisms), and hydrosphere (water bodies). Each of these spheres plays a role in the movement and recycling of carbon.

3. **Explaining Self-Regulation**: The term "self-regulating feedback system" implies that the carbon cycle can adjust itself in response to changes. For example, if there is an increase in carbon dioxide due to human activities, plants may increase their photosynthesis to absorb more CO2, thus helping to regulate the levels of carbon in the atmosphere.

4. **Considering the Reason**: The reason provided states that "the reservoir pool of carbon consists of free CO2 in the atmosphere." This statement is incorrect because while the atmosphere does contain carbon dioxide, the largest reservoir of carbon is actually found in the lithosphere, primarily in the form of fossil fuels and carbonate rocks.

5. **Conclusion**: Based on the analysis, the assertion is true while the reason is false. Therefore, the correct answer is that the assertion is true, but the reason is false.

**Final Answer**: The assertion is true, but the reason is false.

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