Answer:
making the computer-generated models move realistically.
Explanation:
Paul Ernest Debevec is a known personality in the world of computer graphics. As a researcher in computer graphics development, he realized that there are many challenges facing graphics development, and one of the biggest challenges in computer graphics is the ability to make the computer-generated models or human face move realistically.
Hence, in this case, the correct answer is "making the computer-generated models move realistically."
