Answer:
Step-by-step explanation:
The presence or absence of a nucleus is the characteristic that best distinguishes prokaryotic and eukaryotic cells.
In a prokaryotic cell, such as bacteria, the genetic material is not enclosed within a nucleus. Instead, it is present in the cytoplasm in the form of a circular DNA molecule called the nucleoid region. Prokaryotic cells also lack membrane-bound organelles.
On the other hand, eukaryotic cells, found in organisms like plants, animals, and fungi, have a distinct nucleus that houses the genetic material in the form of linear chromosomes. They also contain various membrane-bound organelles, such as mitochondria, endoplasmic reticulum, and Golgi apparatus.
Therefore, the presence of a nucleus and membrane-bound organelles characterizes eukaryotic cells, while their absence defines prokaryotic cells.