Paramecium-

Options

A. Is a ciliated protozoan
B. Shows water current maintained by cillia which helps the food to be steered into gullet
C. Has a cavity (gullet) that opens to the outside of the cell surface
D. All

Answer

### Step-by-Step Solution:

1. **Identify the Organism**: Paramecium is a type of ciliated protozoan, which means it is a single-celled organism that is covered in tiny hair-like structures called cilia.

2. **Understand the Structure**: Paramecium has a unique structure known as the "gullet." The gullet is a cavity that opens to the outside of the cell surface.

3. **Function of Cilia**: The cilia on the surface of Paramecium play a crucial role in movement and feeding. They beat in a coordinated manner to help the organism swim through water.

4. **Role of the Gullet**: The gullet serves as a feeding structure. It helps in the intake of food particles from the surrounding environment. As the cilia move, they create water currents that direct food into the gullet.

5. **Feeding Process**: Once food particles are directed into the gullet, they are then transported into the cell where they can be digested.

6. **Conclusion**: In summary, Paramecium is a ciliated protozoan that uses its cilia for movement and feeding, while the gullet acts as a cavity for food intake.