Final answer:
The Trust controlled the film industry through overseeing patents on key film technologies.
Step-by-step explanation:
The method used by the Trust to control the film industry was overseeing patents on key film technologies. By holding the patents for important film technologies, the Trust had control over who could use and license these technologies, giving them a significant amount of power within the industry. This allowed the Trust to dictate the terms on which other companies could operate and potentially eliminate competition.
Learn more about The method used by the Trust to control the film industry.