Final answer:
Yellow journalism in American newspapers incited public outrage and demand for action in Cuba.
Step-by-step explanation:
The headline that made the US citizens react with outrage and demand that something be done in Cuba was a result of yellow journalism. American newspapers, such as William Randolph Hearst's New York Journal and Joseph Pulitzer's New York World, used sensationalist reporting and inflammatory headlines to agitate for war and increase circulation. By documenting the violence and suffering of the Cuban people under Spanish rule, these newspapers evoked sympathy and support for the Cuban rebels' cause, leading to public outrage in the US.