Armoured cell wall and biflagellated cells are characteristic of :-

Options

A. Chrysophyta
B. Pyrrophyta
C. Euglenophyta
D. Cyanophyta

Answer

To solve the question regarding the characteristics of armoured cell wall and biflagellated cells, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Characteristics**: The question mentions two specific characteristics: "armoured cell wall" and "biflagellated cells". We need to identify which group of organisms exhibits both of these features.

2. **Analyze the Options**: The options provided are:
- Chrysophyta
- Pyrophyta
- Euglenophyta
- Sinophyta

3. **Evaluate Each Option**:
- **Chrysophyta**: This group includes golden algae and diatoms. They are generally not characterized by an armoured cell wall and do not have biflagellated cells.
- **Pyrophyta**: This group is also known as dinoflagellates. They are unicellular algae with a complex cell wall structure that includes cellulosic plates, which form an armoured appearance. Additionally, they possess two unequal flagella, making them biflagellated.
- **Euglenophyta**: This group includes euglenoids, which are also biflagellated but lack a true cell wall. Instead, they have a pellicle, which is a flexible proteinaceous structure.
- **Sinophyta**: This group refers to cyanobacteria, which have a peptidoglycan cell wall and do not possess flagella.

4. **Identify the Correct Group**: Based on the evaluation, Pyrophyta (dinoflagellates) is the only group that possesses both an armoured cell wall and biflagellated cells.

5. **Conclusion**: Therefore, the correct answer to the question is **Pyrophyta**.

### Final Answer:
The correct option is **Pyrophyta**.

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