Answer:
Nucleus
Explanation:
Prokaryotic and Eukaryotic cells are very different from each other and can be distinguished by various characteristic.
But the best indicator that determine whether a cell is a is a prokaryote or eukaryote is the presence of nucleus. Prokaryotic cell do not contain nucleus and their DNA is found in cytoplasm while Eukaryotic cell contains membrane bound nucleus and their DNA is found in nucleus.
Hence, the presence of nucleus would be the best indicator.
