So the major component of the exacerlic matrix is of course, collagen. And collagen as we know, gives the exacer matrix its structure and it gives it tensile strength. Now the other major component of the extracellular matrix in Cartilage is aggregate. The example of the proteoglycan. Now aggregate, what it does is it acts as a lubricant and it asks to actually absorb the shock. It absorbs and dissipates impact forces as we'll see in just a moment.