All protists are unicellular.

Answer

To determine whether the statement "All protists are unicellular" is true or false, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Protists**:
- Protists are a diverse group of eukaryotic organisms. They can be found in various environments, primarily in water.

2. **Characteristics of Protists**:
- Most protists are unicellular, meaning they consist of a single cell. This is a common characteristic of many protists.

3. **Identifying Exceptions**:
- While it is true that the majority of protists are unicellular, there are exceptions. Some protists can be multicellular.

4. **Examples of Multicellular Protists**:
- One notable example of a multicellular protist is kelp, which is a type of brown algae. Kelp can grow quite large and forms underwater forests.

5. **Conclusion**:
- Therefore, the statement "All protists are unicellular" is **false**. While most protists are unicellular, there are multicellular forms as well.

### Final Answer:
The statement "All protists are unicellular" is **false**.

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