Explain the difference between the cars in the 1960's to those from the 1950's

Which of the following statements is true about germany's use of u-boats?

How did slavery end in the united statesa. it ended with the emancipation proclamationb. it ended when the union won the civil warc. it ended with the fifteenth amendmentd. it ended with the 13th amendment

What is the main difference between primary and secondary sources? a. primary sources are historical documents, and secondary sources are modern-day documents. b. primary sources are derived from museums and archives, and secondary sources are created by history students and academics. c. primary sources are found in ancient places with a rich history, and secondary sources are found in historical journals and blogs. d. primary sources are created during a particular historical era, and secondary sources are created by studying primary sources.