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.
The amino acid composition of collagen is atypical for proteins, particularly with respect to its high hydroxyproline content. The most common motifs in the amino acid sequence of collagen are glycine-proline-X and glycine-X-hydroxyproline, where X is any amino acid other than glycine, proline or hydroxyproline.