Show the linkages between a trisaccharide with the sequence GlcA–GlcA–GlcA. The trisaccharide has an ?1?4 glycosidic linkage between the first and second \GlcA monosaccharides. The trisaccharide has a ?1?4 glycosidic linkage between the second and third GlcA monosaccharides. Show stereochemistry using wedge (upward) or dash (downward) bonds.