Which of the following is NOT a similarity between prokaryotes and eukaryotes?

The presence of a nucleus is a key distinction between prokaryotes and eukaryotes, making it the correct choice in this context. Eukaryotic cells contain a defined nucleus that houses their genetic material, separating it from the cytoplasm. In contrast, prokaryotes, such as bacteria, lack a true nucleus; their DNA is not enclosed within a membrane and is typically found in a region called the nucleoid.

Both prokaryotes and eukaryotes share characteristics in their DNA and protein synthesis processes, utilize ribosomes for protein production, and have cytoplasmic environments where cellular activities occur. These shared features highlight the fundamental similarities between these two types of cells, illustrating the evolutionary connections despite their differences, notably in cellular structure and organization.