Final answer:
European immigrants to the US were pushed by factors like religious, political, or racial persecution, famines, and the desire to avoid military service.
Step-by-step explanation:
One "push" factor causing European immigration to the US was the need to escape religious, political, or racial persecution. Many immigrants were pushed from their countries due to ongoing famines or the desire to avoid compulsory military service. For example, Jewish people from the Russian Empire faced discrimination and anti-Semitism, which often led to violence and persecution called pogroms. These push factors influenced immigrants from southern and eastern European countries, such as Italy, Greece, and several Slavic countries including Russia, to seek opportunities in the US.