Final answer:
Eukaryotes are uniquely characterized by a membrane-bound nucleus and other specialized organelles, allowing for advanced cellular organization and processes, distinguishing them clearly from prokaryotes.
Step-by-step explanation:
A unique characteristic of eukaryotes that sets them apart from prokaryotes is the presence of a membrane-bound nucleus. Eukaryotic cells house their genetic material within this nucleus, providing an advanced level of organization and regulation over genetic processes. In addition to the nucleus, eukaryotes have other membrane-bound organelles like mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and peroxisomes that perform specialized functions to maintain cell health and metabolism. These structures allow for compartmentalization within the cell, leading to more efficient cellular functions. Eukaryotes can be single-celled or form complex multicellular organisms, which is another level of complexity not found in prokaryotic life forms.