An independent variable is the variable that the scientist changes,  and the dependent variables are the variables that the scientist  doesn't control.
Glycoprotein VI (platelet) also known as GPVI is a glycoprotein receptor for collagen which is expressed in platelets. In humans, glycoprotein VI is encoded by the GPVI gene.
Collagen is a rich natural source of Glycine. Ligaments (bone to bone connections) and tendons (bone to muscle connections) are `ropes' of collagen. (~80% collagen, the rest proteoglucans and fibroblasts). Collagen, once thought of as a single substance, is now recognized as having many types that contain similar but different molecules.