Glycoproteins:. a. contain unbranched oligosaccharides.
b. are a small fraction of the total number of proteins in a human cell.
c. are many of the cell surface and extracellular proteins.
d. have oligosaccharides covalently attached to aspartate residues.

Explanation:

Glycoproteins have oligosaccharides covalently attached to aspartate residues (type of amino acids) . They are not unbranched oligosaccharides.

Explanation:

Glycoproteins have oligosaccharides covalently attached to aspartate residues.

They are proteins which contain oligosaccharide chains that are covalently attached to the amino acid side-chains.

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