And the extracellular matrix of this cartilage is made up of three types of substances. We have the collagen fibers, we have elastin fibers, and we have proteoglycans. So proteoglycans are proteins that contain our sugar components. The collagen fibers are those proteins that give our cartilage its strength, and the elastin fibers of those proteins that give the cartilage its flexibility. So we have three types of cartilage connective tissues. We have the highland cartilage, we have the elastic cartilage, and we have our fiber cartilage.