What does vertical integration mean in simple terms?

a) hostility to or prejudice against jews.

b) the holocaust, also referred to as the shoah, was a genocide during world war ii in which nazi germany, aided by its collaborators, systematically murdered approximately 6 million european jews             , around two-thirds of the jewish population of europe, between 1941 and 1945.

president thomas jefferson commissioned the expedition shortly after the louisiana purchase in 1803 to explore and to map the newly acquired territory, to find a practical route across the western half of the continent, and to establish an american presence in this territory before britain and other european powers