What is a common structural feature of prokaryotic cells?

Prokaryotic cells are characterized by several structural features, one of the most significant being the presence of a cell wall outside of the plasma membrane. This cell wall serves several important functions: it provides structural support, helps maintain the shape of the cell, and protects it from environmental stresses. In many prokaryotes, the cell wall is composed of peptidoglycan, which distinguishes it from the cell walls found in plant cells (which are made of cellulose) and fungal cells (which are made of chitin).

The lack of a nucleus and membrane-enclosed organelles is a distinguishing feature of prokaryotes, meaning options related to these features would not be applicable here. Additionally, while some prokaryotic cells may form capsules for additional protection, this is not a universal feature across prokaryotic cells nor is it primarily a storage mechanism for DNA. Instead, the DNA in prokaryotic cells is typically located in a region called the nucleoid, which is not surrounded by a membrane. Thus, the presence of the cell wall is the most defining structural characteristic that applies broadly to prokaryotic cells.