Protists having noncontractile vacuole are

Options

A. ciliates
B. dinoflagellates
C. sporozoans
D. euglenoids

Answer

To solve the question regarding which protists have noncontractile vacuoles, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Vacuoles**:
- There are two main types of vacuoles: contractile and noncontractile. Contractile vacuoles are involved in expelling excess water from the cell, while noncontractile vacuoles do not perform this function.

2. **Identify the Organisms**:
- The question lists four options: ciliates, dinoflagellates, corosomes, and cubilinoids. We need to determine which of these have noncontractile vacuoles.

3. **Research Each Option**:
- **Ciliates**: These protists typically have contractile vacuoles to manage water balance.
- **Dinoflagellates**: These organisms possess noncontractile vacuoles, specifically known as "piezole," which help in osmoregulation and flotation.
- **Corosomes**: This term is less commonly used and may not refer to a specific group known for noncontractile vacuoles.
- **Cubilinoids**: This group is not widely recognized in the context of vacuoles.

4. **Conclude the Correct Answer**:
- Based on the information gathered, dinoflagellates are the protists that have noncontractile vacuoles. They are responsible for osmoregulation and flotation.

### Final Answer:
The protists having noncontractile vacuoles are **dinoflagellates**.

---