What are non-membranous organelles that contribute to the cytoskeleton?

The correct answer highlights microfilaments as non-membranous organelles that play a crucial role in maintaining the structure and stability of the cell’s cytoskeleton. Microfilaments are made primarily of actin, a protein that is vital for various cellular functions, including maintaining the cell's shape, enabling movement, and facilitating intracellular transport. They are a fundamental component of the cytoskeleton, which is responsible for providing mechanical support, allowing for cellular rigidity, and participating in cellular processes such as division and motility.

Other choices in the question, while important in cellular function, do not fit the criteria of non-membranous organelles related to the cytoskeleton. Ribosomes, for example, are involved in protein synthesis and are also non-membranous but do not contribute to the cytoskeletal structure. Mitochondria are membrane-bound organelles responsible for energy production, while lysosomes are involved in digestion and waste removal and contain a membrane. Thus, the emphasis on microfilaments clearly demonstrates their essential role in the cytoskeleton, distinguishing them from the other options provided.