Name the most abundant protein in the whole of the biosphere.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of the most abundant protein present in the biosphere. This means we need to identify the protein that exists in the highest quantity across all living organisms.

2. **Identifying the Protein**: After considering various proteins found in nature, we find that Rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is recognized as the most abundant protein.

3. **Function of Rubisco**: Rubisco plays a crucial role in the process of photosynthesis. Specifically, it is an enzyme that facilitates carbon fixation, which is the first step in the Calvin cycle. This process is essential for converting carbon dioxide into organic compounds that can be utilized by plants.

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