Step 1: Recall the genome of prokaryotes.
Prokaryotes (bacteria) have a single circular DNA molecule as their genetic material, located in the nucleoid region.
Step 2: Presence or absence of histones.
Prokaryotes lack histones. Histones are found in eukaryotes, where they facilitate DNA packaging into chromatin.
Step 3: Checking options.
- Option (1): Incorrect. DNA is present; histones are absent.
- Option (2): Incorrect. DNA is always present.
- Option (3): Correct. DNA is present, and histones are absent in prokaryotes.
- Option (4): Incorrect. Histones are exclusively found in eukaryotes.
Step 4: Conclusion.
The prokaryotic genetic system consists of DNA, but not histones.