What best defines the underground railroad? the train route from baltimore to philadelphia, the subway system in new york, the escape route for runaway slaves.

The escape route for runaway slaves.

Explanation:

The Underground Railroad was a network of clandestine routes existing in the United States during the eighteenth century, which was used for the escape of African slaves to the northern states or to Canada, who were free of slavery, with the help of abolitionists. Other routes took them to Mexico.

small european communities with shared traditions consolidated into large new states (apex)