History of the holocaust. Please help!

Describe the technology advancements that lead to explorers being able to sail great distances. [[ps: doesn't explain where. i am only speculating it's in europe.

Explain how zollverein, a tariff agreement, to unite the german states.

Which impact did the civil war have on the spread of disease in texas a. disease decreased bc people left the area to fight in the war b. disease increased bc medicine was in short supply. c. disease increased bc many new diseases were brought to the area d. disease decreased bc confederate doctors distribute new medicines to local communities