A primitive filament is formed in protist

Options

A. Gonyaulax
B. Gymnodinium
C. Melosira
D. Pinnularia.

Answer

To determine which protist forms a primitive filament, we can follow these steps:

### Step 1: Understand the Concept of Primitive Filaments
Primitive filaments are structures formed by the joining of cells in a chain-like manner. In the context of protists, we need to identify which of the given options can form such structures.

### Step 2: Analyze the Given Options
We have several protists to consider:
- Gonulax
- Gymnodinium
- Melocera
- Pinoleria

### Step 3: Evaluate Each Option
1. **Gonulax**: This is a freshwater algae. Since it is not known for forming primitive filaments, we can eliminate this option.
2. **Gymnodinium**: This is also a freshwater algae and does not form primitive filaments. Thus, this option is also eliminated.
3. **Melocera**: Melocera is identified as a type of diatom. Diatoms are known for their silica-based cell walls and can form long filamentous chains, making this a potential candidate for forming primitive filaments.
4. **Pinoleria**: Like the previous two, Pinoleria is a freshwater algae and does not form primitive filaments. Therefore, this option is eliminated.

### Step 4: Conclusion
After evaluating all the options, we conclude that the correct answer is **Melocera**, as it is the only protist among the options that forms primitive filaments.

### Summary of the Solution
The primitive filament is formed in the protist **Melocera**, which is a type of diatom that can form long filamentous chains.

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