Find out incorrect sentence

Options

A. Protista includes unicellular eukaryotic organisms
B. Whittaker considered cell structure, mode and source of nutrition for classifying the organisms in five kingdoms
C. Both Monera and Protista may be autotrophic and heterotrophic
D. Monerans have well defined nucleus

Explanation

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks us to identify the incorrect sentence among the given options regarding living organisms and their classification.

2. **Analyze Each Option**:
- **Option 1**: "Protests include unicellular eukaryotic organisms."
- This statement is correct. The kingdom Protista does include unicellular eukaryotic organisms such as protozoans and unicellular algae.

- **Option 2**: "Whittaker considered cell structure, mode and source of nutrition for classifying the organisms in the five kingdoms."
- This statement is also correct. R.H. Whittaker's five-kingdom classification indeed considered cell structure and modes of nutrition.

- **Option 3**: "Both Monera and Protista may be autotrophic or heterotrophic."
- This statement is correct as well. Monera includes bacteria that can be autotrophic or heterotrophic, and Protista includes both types of organisms.

- **Option 4**: "Monerans have a well-defined nucleus."
- This statement is incorrect. Monerans (prokaryotes) do not have a well-defined nucleus; instead, they have a nucleoid region which lacks a nuclear membrane.

3. **Identify the Incorrect Sentence**: After analyzing all the options, we conclude that option 4 is the incorrect statement because Monerans do not have a well-defined nucleus.

4. **Final Answer**: The incorrect sentence is option 4: "Monerans have well-defined nucleus."

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