Enotes policy allows me to answer one question per post. I will answer the question you posted about yellow journalism.
Yellow journalism refers to when a media outlet exaggerates news stories. In the late 1890s, the United States was looking to expand overseas. The newspapers played a role in turning public opinion against Spain. The Spanish had been mistreating the people in Cuba. The newspapers over-exaggerated this mistreatment. While the mistreatment wasn’t good, the newspapers made it sound much worse than it really was. Since the newspaper was the main way people could get news in the 1890s, especially regarding foreign events, there was no way to check the validity of the news stories.
As public opinion turned against Spain, more people began to think we should intervene to help the Cubans. After the USS Maine sank in the waters off the Cuban coast, people jumped to the conclusion that the Spanish were responsible. The pressure to declare war on Spain increased. President McKinley did ask Congress to declare war on Spain, beginning the Spanish-American War in 1898.