What invention most increased the influence of films on culture and society in the twentieth century?

the cinematograph
the addition of newsreels
the creation of feature-length films
the innovation of sound

The innovation of sound in films is considered to be the invention that most increased the influence of films on culture and society in the twentieth century. Sound allowed for greater immersion in the film-watching experience, as viewers could now hear dialogue, music, and sound effects. This significantly enhanced the emotional impact of films and expanded the storytelling possibilities, making films a more powerful medium for conveying messages and influencing public opinion. Additionally, the introduction of sound attracted a wider audience to cinemas, boosting the industry's popularity and influence on global culture.