Final answer:
Edwin S. Porter and D.W. Griffith contributed to the rapid advancement of filmmaking by introducing narrative editing techniques, close-ups, and cross-cutting.
Step-by-step explanation:
Two Americans, Edwin S. Porter and D.W. Griffith, made significant contributions to the advancement of filmmaking as an art form and mass entertainment. Edwin S. Porter developed narrative editing techniques, which involved using different shots and scenes to tell a story. D.W. Griffith introduced close-ups, which allowed for more emotional impact and emphasized important details, as well as cross-cutting, which added tension and created parallel storylines. These innovations revolutionized the way films were made and set the foundation for modern filmmaking techniques.