What are the structures that enable bacteria to move?

The correct answer identifies flagella and cilia as structures that enable bacteria to move. Flagella are long, whip-like appendages that propel bacteria through their environment, allowing for rapid movement. They rotate like a propeller and can vary in number and arrangement on different bacterial species, contributing to various movement patterns.

Cilia, although more commonly associated with eukaryotic cells, can also be present in some protozoan microorganisms. In the context of bacteria specifically, the presence of flagella is the more significant means of motility, but cilia get mentioned interchangeably in wider biological discussions.

The other options indicate structures that are not primarily involved in locomotion. Pili and fimbriae, for instance, are mainly used for attachment to surfaces and other cells rather than for movement. They help with adhesion rather than propulsion. The cell wall provides structural support and shape but does not enable movement on its own. Understanding these distinctions is key to grasping bacterial mobility mechanisms.