Final answer:
Microtubules are correctly described as hollow structures, being the thickest elements of the cytoskeleton and essential for cell shape and division. Actin filaments are thin and involved in muscle contraction and cell movement. Intermediate filaments provide tensile strength and are rope-like, but are not hollow.
Step-by-step explanation:
The protein filament correctly matched with its feature is microtubules/hollow. Microtubules are small hollow tubes made of dimers of α-tubulin and β-tubulin which form the walls of these cylindrical structures. They are the thickest component of the cytoskeleton and play an important role in maintaining cell shape, enabling intracellular transport, and organizing the mitotic spindle during cell division. In contrast, actin filaments, also known as microfilaments, are composed of two intertwined strands of actin and are much thinner. They are responsible for muscle contraction, cell movement, and maintaining cell shape. Intermediate filaments are indeed rope-like in structure and provide tensile strength to cells, but they are not hollow; they are composed of proteins, such as keratin, that are wound together.