The prokaryotic genetic system contains :
(a) either DNA or histones
(b) neither DNA nor histones
(c) DNA and histones
(d) DNA but no histones

Options

A. either DNA or histones
B. neither DNA nor histones
C. DNA and histones
D. DNA but no histones

Explanation

To solve the question regarding the prokaryotic genetic system, we need to analyze the options provided and understand the characteristics of prokaryotic cells.

### Step-by-Step Solution:

1. **Understanding Prokaryotes**: Prokaryotes are unicellular organisms that lack membrane-bound organelles, including a nucleus. Instead, they have a region called the nucleoid where their genetic material is located.

2. **Genetic Material in Prokaryotes**: The genetic material in prokaryotes is primarily composed of a single, circular, double-stranded DNA molecule. This DNA is not associated with histones, which are proteins that help package DNA in eukaryotic cells.

3. **Evaluating the Options**:
- **Option (a)**: "either DNA or histones" - This is incorrect because prokaryotes have DNA but do not have histones.
- **Option (b)**: "neither DNA nor histones" - This is incorrect because prokaryotes do have DNA.
- **Option (c)**: "DNA and histones" - This is incorrect because prokaryotic DNA is not associated with histones.
- **Option (d)**: "DNA but no histones" - This is correct as prokaryotes contain DNA but do not have histones for packaging.

4. **Conclusion**: Based on the characteristics of prokaryotic cells, the correct answer is (d) DNA but no histones.

### Final Answer:
(d) DNA but no histones

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