11. Which organelle is known as nonmembranous organelle in cytoplasm? A. Plasma membrane B. Smooth -surfaced reticulum (sER) C. Rough -surfaced endoplasmic reticulum (rER) D. Microtubules

The correct answer is D. Microtubules.<br /><br />Microtubules are nonmembranous organelles found in the cytoplasm of cells. They are composed of tubulin proteins and play a crucial role in maintaining the structure of cells, facilitating intracellular transport, and enabling cell division. Unlike the other options, microtubules do not have a membrane surrounding them, making them nonmembranous organelles.