The mineral ion that acts as an activator for both RuBisCo and PEP case enzyme is

Options

A. Copper
B. Magnesium
C. Zinc.
D. Molybdenum

Answer

To solve the question regarding the mineral ion that acts as an activator for both RuBisCo and PEP case enzymes, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Enzymes**:
- RuBisCo (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is a crucial enzyme in the Calvin cycle (C3 pathway) of photosynthesis.
- PEP case (Phosphoenolpyruvate carboxylase) is an enzyme involved in the C4 pathway of photosynthesis.

2. **Identifying the Role of Mineral Ions**:
- Enzymes often require metal ions as cofactors to function properly. These ions can act as activators, enhancing the enzyme's activity.

3. **Evaluating the Options**:
- **A. Copper**: Not primarily known as an activator for RuBisCo or PEP case.
- **B. Magnesium**: Known to be an essential cofactor for many enzymes, including RuBisCo and PEP case.
- **C. Zinc**: While it plays a role in various enzymes, it is not specifically known for activating RuBisCo or PEP case.
- **D. Molybdenum**: Important for some enzymes but not specifically for RuBisCo or PEP case.

4. **Conclusion**:
- Based on the evaluation, the mineral ion that acts as an activator for both RuBisCo and PEP case enzymes is **Magnesium**.

### Final Answer:
The correct option is **B. Magnesium**.