Which of the following pairs is an example of the sedimentary type of biogeochemical cycle?

Options

A. Oxygen and nitrogen
B. Phosphorus and sulphur
C. Phosphorus and nitrogen
D. Phosphorus and carbon dioxide

Answer

To solve the question regarding which pair represents an example of the sedimentary type of biogeochemical cycle, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Biogeochemical Cycles:**
- Biogeochemical cycles are pathways through which essential elements and compounds circulate through the environment, involving both biotic (living) and abiotic (non-living) components.
- These cycles can be classified into two main types: gaseous and sedimentary.

2. **Identifying Sedimentary Cycles:**
- Sedimentary cycles involve elements that are primarily found in solid form and do not have a gaseous phase in their cycle.
- Examples of elements involved in sedimentary cycles include phosphorus, calcium, and magnesium.

3. **Analyzing the Options:**
- **Option a:** Oxygen and Nitrogen - Both are primarily gaseous elements.
- **Option b:** Phosphorus and Sulphur - Phosphorus is a sedimentary element, and sulphur can exist in both gaseous and sedimentary forms.
- **Option c:** Phosphorus and Nitrogen - Phosphorus is sedimentary, but nitrogen is gaseous.
- **Option d:** Phosphorus and Carbon Dioxide - Phosphorus is sedimentary, but carbon dioxide is gaseous.

4. **Determining the Correct Pair:**
- The only pair that includes a sedimentary element is **Option b: Phosphorus and Sulphur**. While sulphur can exist in both forms, phosphorus is definitively a sedimentary element.

5. **Conclusion:**
- Therefore, the correct answer to the question is **Option B: Phosphorus and Sulphur**.