The issue focused on the problem of using the Phong data model to represent the human population. The author used the Phong data model to represent the human population. The Phong data model is a complete 3-dimensional model of the data. The Phong data model is a complete 3-dimensional model of the data. The Phong data model is a complete 3-dimensional model of the data. The Phong data model is a complete 3-dimensional model of the data. The Phong data model is