How did Persia become involved in the Peloponnesian Wars? Sparta had destroyed the Athenian navy, so Persia attacked Sparta.
The Persians had burned Athens, so Persia was attacked by Sparta.
Athens had defeated Persia at the Battle of Salamis, so Persia supported Sparta.
Sparta had resisted Persia at the Battle of Thermopylae, so Persia supported Athens.

Read the summary about factory work during the industrial revolution. with the development of new technologies and manufacturing processes, the nature of factory work changed. now, machines could do the heavy labor formerly done by men. this meant that women and children could work in factories. in fact, factories sometimes hired entire families. they earned hourly wages. while this could bring in a steady income, that income was not high. women earned less than men, and children’s wages were especially low. the underlined sentence identifies a central trend. provides some key details. makes clear the writer’s opinion. states the main idea of the summary.