Which of the following is a gaseous cycle?

Options

A. sulphur cycle
B. phosphorus cycle
C. nitrogen cycle
D. all of these

Answer

To determine which of the following is a gaseous cycle, we can analyze each option provided:

1. **Sulfur Cycle**: The sulfur cycle involves the movement of sulfur through the atmosphere, lithosphere, and hydrosphere. However, it primarily includes sedimentary processes and is not classified as a gaseous cycle.

2. **Phosphorus Cycle**: The phosphorus cycle is predominantly a sedimentary cycle. Phosphorus is mainly found in rocks and soil, and it does not have a significant gaseous phase in its cycle.

3. **Nitrogen Cycle**: The nitrogen cycle is a classic example of a gaseous cycle. It involves the conversion of nitrogen gas (N2) in the atmosphere into various forms usable by living organisms, such as ammonia and nitrates, and then back into nitrogen gas.

4. **All of These**: This option suggests that all the cycles mentioned are gaseous cycles, which is incorrect based on the definitions of the cycles.

Based on the analysis, the correct answer is the **Nitrogen Cycle**.

### Step-by-Step Solution:
1. **Identify the cycles**: Look at each option provided (sulfur, phosphorus, nitrogen).
2. **Classify the cycles**: Determine if they are gaseous or sedimentary. Sulfur and phosphorus cycles are sedimentary.
3. **Focus on the nitrogen cycle**: Recognize that the nitrogen cycle involves atmospheric nitrogen and is classified as a gaseous cycle.
4. **Eliminate incorrect options**: Since sulfur and phosphorus are not gaseous cycles, they can be eliminated.
5. **Select the correct answer**: The only gaseous cycle among the options is the nitrogen cycle.