Which of the following was integral to the growth of the entire nation during the early 1900s? traffic signal gas mask the hair straightener u. s steel how did henry ford expand his business internationally? he signed contracts with the us government. he opened up plants in other countries. he sold off portions of his company to international buyers. none of the above. though lewis henry latimer made contributions to the lightbulb, he was not considered a key person involved in its development. true false