most abundant enzyme is

Options

A. catalase
B. RuBisCO
C. Nitrogenase
D. Invertase

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the most abundant enzyme. We need to evaluate the options provided.

2. **Analyzing the Options**:
- **Option 1: Catalyst** - This is a general term for substances that speed up chemical reactions, but it is not a specific enzyme.
- **Option 2: Rubisco** - This is an enzyme involved in the process of photosynthesis, specifically in the fixation of carbon dioxide.
- **Option 3: Nitrogen** - This is an element, not an enzyme.
- **Option 4: Invertase** - This is an enzyme that catalyzes the hydrolysis of sucrose into glucose and fructose, but it is not the most abundant.

3. **Identifying the Most Abundant Enzyme**: Among the options, Rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is known to be the most abundant enzyme on Earth. It plays a crucial role in the Calvin cycle of photosynthesis by fixing carbon dioxide.

4. **Conclusion**: Based on the analysis, the correct answer is **Option 2: Rubisco**.