Final answer:
Archaea lack histone H1, which prevents them from forming the 30 nm fiber of chromatin, as they do not organize their chromosomes with histone proteins like eukaryotes.
Step-by-step explanation:
Archaea have no histone H1. As a result, it is unable to form the 30 nm fiber of chromatin. While eukaryotic chromosomes are organized around histone proteins into a structure known as chromatin, archaea lack these eukaryotic histones and therefore do not form the same chromatin structure. This is because the prokaryotic chromosomes of archaea and bacteria are typically circular and not associated with histone proteins in the same way as eukaryotic chromosomes.