Final answer:
The cytoskeleton is the cell component primarily composed of protein, providing structural support and facilitating movement.
Step-by-step explanation:
Of the following cell components, which is composed primarily of protein is the cytoskeleton. The cytoskeleton is a network within the cell composed of protein fibers, including microfilaments (actin filaments), intermediate filaments, and microtubules. These proteins help maintain the cell's shape, secure organelles in specific positions, allow movement within the cell, and enable independent movement in unicellular organisms. For instance, intermediate filaments are comprised of fibrous proteins and provide support and tension resistance. The cytoskeleton also scaffolds the organelles within the cell, serving a critical structural and functional role.