In the given options , there is q property of a group and a representative example following that property . Which of these is incorrect ?

Options

A. All prokaryotes classified under kingdom Monera have cell wall ( Mycoplasma )
B. All viroids have single stranded RNA as genetic material ( Potato Tube spindle Viroid )
C. All Prions don't have nucleic acid as their genetic material ( Bovine Spongiform Encephalopathy prion )
D. Unicellular plants have been placed in Kingdom Protista by Whittaker (Chlorella)

Answer

To solve the question, we need to evaluate each option provided in terms of the property of the group and its representative example. We are looking for the incorrect pair.

### Step-by-Step Solution:

1. **Option 1: All prokaryotes classified under kingdom Monera have cell walls; Example: Mycoplasma**
- **Analysis**: This statement is incorrect because Mycoplasma is a type of prokaryote that does not have a cell wall. Therefore, this is the incorrect representative example.

2. **Option 2: All viroids have single-stranded RNA as the genetic material; Example: Potato spindle tuber viroid**
- **Analysis**: This statement is correct. Viroids are indeed known to have single-stranded RNA as their genetic material, and the potato spindle tuber viroid is a well-known example.

3. **Option 3: All prions don't have nucleic acid as their genetic material; Example: Spongiform encephalopathy prion**
- **Analysis**: This statement is also correct. Prions are infectious agents that do not contain nucleic acids, and spongiform encephalopathy is a disease caused by prions.

4. **Option 4: Unicellular plants have been placed in the kingdom Protista by Whittaker; Example: Chlorella**
- **Analysis**: This statement is correct. Chlorella is a unicellular green alga that is classified under the kingdom Protista.

### Conclusion:
The incorrect option is **Option 1**: All prokaryotes classified under kingdom Monera have cell walls; Example: Mycoplasma.

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