______ is the most abundant protein in animal world and _____ is the most abundant protein in the whole biosphere.

Options

A. Collagen, RuBisCO
B. Collagen, keratin
C. Keratin, RuBisCO
D. Keratin, collagen

Explanation

To answer the question regarding the most abundant proteins in the animal world and the whole biosphere, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Most Abundant Protein in the Animal World**:
- The question asks for the most abundant protein specifically in the animal kingdom.
- The answer is **Collagen**. Collagen is a structural protein that forms a significant part of connective tissues, such as skin, tendons, ligaments, and cartilage. It is known for its role in providing strength and support to various tissues in animals.

2. **Identify the Most Abundant Protein in the Whole Biosphere**:
- Next, we need to determine the most abundant protein across all living organisms on Earth.
- The answer is **Rubisco** (Ribulose-1,5-bisphosphate carboxylase/oxygenase). Rubisco is an enzyme that plays a crucial role in the process of photosynthesis by catalyzing the fixation of carbon dioxide. It is found in all plants and is essential for the conversion of carbon dioxide into organic compounds.

3. **Combine the Answers**:
- Therefore, the complete answer to the question is: **Collagen is the most abundant protein in the animal world, and Rubisco is the most abundant protein in the whole biosphere**.

### Final Answer:
**Collagen** is the most abundant protein in the animal world, and **Rubisco** is the most abundant protein in the whole biosphere.

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