Final answer:
The newly discovered hormone, consisting of four amino acids, would be classified as an amino acid-derived hormone.
Step-by-step explanation:
The newly discovered hormone, which contains a chain of four linked amino acids, would be classified into the category of amino acid-derived hormones.
Amino acid-derived hormones are water insoluble and require a cell surface receptor. They include hormones such as epinephrine, thyroxine, and melatonin.
Unlike lipid-derived hormones that can diffuse across plasma membranes, amino acid-derived hormones, such as the newly discovered hormone in question, cannot.