Which of the following statement/s is/are not the characteristic feature of kingdom Protista?
(a) They include chrysophytes, dinoflagellates, euglenoids, slime molds, and protozoans
(b) Chief producers in the ocean are diatoms.
(c) Toxins are released by some of the members of this kingdom.
(d) They are either unicellular or multicellular.

Options

A. a and c
B. b and d
C. b and c
D. Only d

Answer

To determine which statement is not a characteristic feature of the kingdom Protista, we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Kingdom Protista**:
- Kingdom Protista primarily consists of unicellular eukaryotic organisms. These organisms have a well-defined nucleus and membrane-bound organelles.

2. **Analyzing Statement (a)**:
- The statement mentions that Protista includes chrysophytes, dinoflagellates, euglenoids, slime molds, and protozoans.
- **Analysis**: This is correct as all these groups are indeed part of the kingdom Protista.

3. **Analyzing Statement (b)**:
- The statement claims that the chief producers in the ocean are diatoms.
- **Analysis**: This is also correct. Diatoms are a type of phytoplankton and are significant primary producers in marine ecosystems.

4. **Analyzing Statement (c)**:
- This statement indicates that toxins are released by some members of this kingdom.
- **Analysis**: This is true; certain dinoflagellates can produce toxins, leading to phenomena like red tides.

5. **Analyzing Statement (d)**:
- The statement asserts that organisms in Protista can be either unicellular or multicellular.
- **Analysis**: This is incorrect. While there are multicellular organisms in other kingdoms (like Plantae and Animalia), Protista is primarily characterized by unicellular organisms.

### Conclusion:
- The statement that is **not a characteristic feature of kingdom Protista** is **(d)**: "They are either unicellular or multicellular."

### Final Answer:
**(d)** is the statement that is not a characteristic feature of kingdom Protista.

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