Which element generally activates decarboxylase enzyme?

Options

A. Mo
B. Mn
C. Mg
D. Zn

Answer

To determine which element generally activates decarboxylase enzymes, we can analyze the given options one by one:

1. **Molybdenum (Option A)**:
- Molybdenum is known to be a component of several enzymes, such as nitrogenase and nitrate reductase. However, it does not activate decarboxylase enzymes. Therefore, this option is incorrect.

2. **Manganese (Option B)**:
- Manganese is absorbed from the soil in the form of manganese ions (Mn²⁺). It is known to activate many enzymes, including decarboxylase enzymes. Therefore, this option is correct as manganese plays a significant role in activating enzymes involved in photosynthesis, respiration, and nitrogen metabolism.

3. **Magnesium (Option C)**:
- Magnesium is another essential element that activates various enzymes. However, it does not specifically activate decarboxylase enzymes. Thus, this option is also incorrect.

4. **Zinc (Option D)**:
- Zinc is involved in activating certain enzymes, particularly carboxylases. However, it does not activate decarboxylase enzymes. Therefore, this option is incorrect as well.

Based on the analysis, the element that generally activates decarboxylase enzymes is **Manganese (Option B)**.

### Summary:
The correct answer is **B. Manganese**.