Why are carbon and nitrogen cycles called gaseous cycles ?

Explanation

**Step-by-Step Solution:**

1. **Understanding Biogeochemical Cycles**: Biogeochemical cycles are processes that recycle nutrients in various chemical forms from the environment to organisms and then back to the environment. These cycles can be classified into two main types: sedimentary cycles and gaseous cycles.

2. **Defining Gaseous Cycles**: Gaseous cycles are those in which the main reservoir of the nutrient is found in the atmosphere. The primary elements involved in gaseous cycles include carbon and nitrogen.

3. **Identifying the Reservoir**: The key difference between gaseous cycles and sedimentary cycles lies in their reservoirs. In gaseous cycles, the reservoir is in the form of gases present in the atmosphere. For example, carbon exists as carbon dioxide (CO2) in the atmosphere, and nitrogen exists as nitrogen gas (N2).

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