Click on the sentence that has an error in verb tense. Harriet Tubman was one important figure in the history of the Underground Railroad. She was a slave herself, but she was able to escape to freedom when she was around twenty-seven years old. Tubman used the Underground Railroad to make her way from slavery in Maryland to freedom in Pennsylvania. However, Tubman soon returned to Maryland and helped her family members escape to freedom. Tubman has traveled along various routes of the Underground Railroad over a dozen times, and she helped many people escape the horrors of slavery.

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Which of these was not a component of the american system? a) protective tariff b) internal improvements c) universal manhood suffrage eliminate d) the 2nd bank of the united states

The health care system in is referred to as a singleminus−payer health care system, and is a system in which the government provides national health insurance to all residents.

The authors of the paper "fudging the numbers: distributing chocolate influences student evaluations of an undergraduate course"† carried out a study to see if events unrelated to an undergraduate course could affect student evaluations. students enrolled in statistics courses taught by the same instructor participated in the study. all students attended the same lectures and one of six discussion sections that met once a week. at the end of the course, the researchers chose three of the discussion sections to be the "chocolate group." students in these three sections were offered chocolate prior to having them fill out course evaluations. students in the other three sections were not offered chocolate. the researchers concluded that "overall, students offered chocolate gave more positive evaluations than students not offered chocolate." indicate whether the study is an observational study or an experiment. give a brief explanation for your choice.