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

Options

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

Explanation

To solve the question regarding the prokaryotic genetic system, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Prokaryotic Cells**:
- Prokaryotic cells are simple, unicellular organisms that lack a nucleus and membrane-bound organelles. Their genetic material is not enclosed within a nuclear membrane.

2. **Identifying Genetic Material**:
- In prokaryotes, the genetic material is present in a region called the nucleoid. This nucleoid contains the DNA of the organism.

3. **Nature of Prokaryotic DNA**:
- The DNA in prokaryotes is typically found in a circular form. It can be single-stranded or double-stranded but is primarily circular in structure.

4. **Histones in Prokaryotes**:
- Histones are proteins that help in the packaging of DNA in eukaryotic cells. However, prokaryotic DNA does not require histones for packaging because of its circular structure and the way it is organized within the nucleoid.

5. **Evaluating the Options**:
- (a) Either DNA or histones: Incorrect, as prokaryotes have DNA but no histones.
- (b) DNA but no histones: Correct, as prokaryotes contain DNA and do not have histones.
- (c) Neither DNA nor histones: Incorrect, as prokaryotes do have DNA.
- (d) DNA and histones: Incorrect, as prokaryotes do not have histones.

6. **Conclusion**:
- The correct answer is (b) DNA but no histones.

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