 Complete the following phrase:  Following the invasion of Poland in 1939 most of the 3.5 million Polish Jews were rounded up and confined to newly established ghettos by Nazi Germany. The system was intended to isolate the Jews from the outside world in order to facilitate their exploitation and abuse. The supply of food was inadequate, living conditions were cramped and unsanitary, and the Jews had no way to earn money. Malnutrition and lack of medicine led to soaring mortality rates. In 1941, the 