A sedentary ciliate is

Options

A. Paramecium
B. Tetrahymena
C. Vorticella
D. Balantidium.

Answer

To determine which of the given options is a sedentary ciliate, we will analyze each option based on the definition of "sedentary" and the characteristics of each organism.

### Step 1: Understand the term "sedentary"
- The term "sedentary" refers to organisms that are inactive or stationary, meaning they do not move from one place to another.

**Hint:** Remember that sedentary organisms are typically attached to a surface and do not exhibit locomotion.

### Step 2: Analyze the first option - Paramecium
- Paramecium is a well-known ciliate that uses its cilia for locomotion and feeding. It actively moves through its environment.

**Hint:** If an organism is known for its movement and feeding behavior, it is likely not sedentary.

### Step 3: Analyze the second option - Tetrahymena
- Similar to Paramecium, Tetrahymena also possesses cilia that allow it to swim and move actively in water.

**Hint:** Look for characteristics that indicate movement; if an organism is mobile, it cannot be sedentary.

### Step 4: Analyze the third option - Vorticella
- Vorticella is a cup-shaped ciliate that has a stalk. This stalk attaches it to a substrate, making it stationary. It does not move from this position, which aligns with the definition of a sedentary organism.

**Hint:** A key feature of sedentary organisms is that they are anchored to a surface, limiting their movement.

### Step 5: Analyze the fourth option - Balantidium
- Balantidium is another ciliate that uses cilia for movement and is not sedentary. It actively moves in its environment.

**Hint:** Assess whether the organism is known for its ability to move; if it is, it is not sedentary.

### Conclusion
Based on the analysis, the correct answer is **Vorticella**, as it is the only organism among the options that is sedentary due to its attachment to a substrate.

**Final Answer:** Vorticella is a sedentary ciliate.