Final answer:
Archaea lack histone H1, which prevents them from forming the 30 nm fiber of chromatin found in eukaryotic cells. Instead, prokaryotic chromosomes rely on DNA supercoiling and histone-like proteins for DNA packaging.
Step-by-step explanation:
Archaea lack histone H1. Without histone H1, Archaea are unable to form the 30 nm fiber of chromatin, which is a more compact structure of DNA that is seen in eukaryotic cells. Prokaryotes, which include both bacteria and archaea, generally have one circular chromosome that is not associated with histones in the same way as eukaryotic chromosomes. In prokaryotic chromosomes, DNA supercoiling and histone-like proteins aid in DNA packaging to fit the genome within the relatively small cell volume.