Dinoflagellates have-

Options

A. A single flagellum in the transverse groove between the cell plates
B. A single flagellum in the longitudinal groove between the cell plates
C. Two flagella one lies longitudinally and the other transversely in a furrow between the wall plates
D. No flagella

Answer

**Step-by-Step Solution:**

1. **Understanding Dinoflagellates**: Dinoflagellates are a group of microorganisms that are characterized by their unique structure and movement. They are primarily found in marine and freshwater environments.

2. **Flagella Structure**: Dinoflagellates possess two types of flagella:
- **Longitudinal Flagellum**: This flagellum runs along the length of the cell and is responsible for forward movement.
- **Transverse Flagellum**: This flagellum encircles the cell in a groove and helps in steering and stabilization.

3. **Correct Option Identification**: According to the information provided, the correct statement regarding the flagella of dinoflagellates is that they have two flagella: one longitudinal and one transverse, which are positioned in a furrow between the cell plates.

4. **Elimination of Incorrect Options**: The options stating that dinoflagellates have only a single flagellum (either longitudinal or transverse) are incorrect. This is because dinoflagellates are specifically known for having both types of flagella.

5. **Conclusion**: Therefore, the correct answer is that dinoflagellates have two flagella: one longitudinal and one transverse, positioned in a furrow between the cell plates.

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