* Cell wall: While some eukaryotes have cell walls (like plants and fungi), it's a defining feature of prokaryotes.

* Ribosomes: Both prokaryotes and eukaryotes have ribosomes, but the ribosomes in prokaryotes are smaller (70S) than those in eukaryotes (80S).

* Circular DNA: Prokaryotes have a single, circular chromosome located in a region called the nucleoid. Eukaryotes have linear chromosomes within a membrane-bound nucleus.

The combination of these features strongly points to a prokaryotic cell.