The clаdоgrаm shоwn belоw depicts аn accepted model of the evolutionary relationships among selected species. The figure shows a cladogram with the root at the bottom left and three branches. From left to right, the branches are as follows: Horse, with a point labeled W; Gorilla, with a point labeled X, and Human, with a point labeled Y. Past the branches, the main line is labeled Chimpanzee, with a point labeled Z. The amino acid at position 104 in the beta-hemoglobin protein for each of these four organisms is listed below. Amino acid at position 104 in the beta-hemoglobin protein Species Amino Acid 104 Horse Arginine Gorilla Leucine Human Arginine Chimpanzee Arginine The validity of the cladogram is best supported by molecular evidence for which of the following changes in the amino acid composition of the beta-hemoglobin protein during the evolution of these species?