Which one of the following is a saprophytic protist?

Options

A. Desmid
B. Slime mould
C. Euglena
D. Gonyaulax

Answer

To determine which of the given options is a saprophytic protist, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Saprophytic Protists**:
- Saprophytic organisms obtain their nutrients by feeding on dead and decaying organic matter.

2. **Analyze the Options**:
- **A. Desmid**: Desmids are green algae and primarily photosynthetic, not saprophytic.
- **B. Slime Mold**: Slime molds are known to feed on decaying organic matter, making them saprophytic.
- **C. Euglena**: Euglena are primarily photosynthetic but can also exhibit heterotrophic behavior; however, they are not classified as saprophytic.
- **D. Goniolex**: Goniolex belongs to the dinoflagellates, which are also not saprophytic.
- **E. Olex**: This option is not clearly defined in the context of protists.

3. **Identify the Correct Answer**:
- Based on the analysis, slime molds (Option B) are the only organisms listed that are classified as saprophytic protists.

4. **Conclusion**:
- Therefore, the correct answer is **B. Slime Mold**.