What role do microtubules play in a cell?

Microtubules are crucial components of the cytoskeleton in eukaryotic cells and play a significant role in maintaining the cell's shape. They are rigid, hollow structures made of tubulin protein subunits, which provide structural support to the cell. This structural integrity allows cells to maintain their shape under various conditions, facilitating normal cellular functions and interactions with the environment.

In addition to maintaining shape, microtubules are involved in several processes such as cell division, intracellular transport, and the movement of cilia and flagella, contributing to the overall functionality of the cell. Their dynamic nature allows them to grow and shrink as needed, which is essential for various cellular activities. The other options, while related to cellular functions, do not accurately describe the primary role of microtubules within the cell.