Final answer:
Young Jewish men were selected to work in the crematoria or 'gas-chambers' as part of the systematic extermination of Jews during the Holocaust.
Step-by-step explanation:
The young Jewish men who were selected to work in the crematoria or 'gas-chambers' were part of the systematic extermination of Jews by the Nazis during the Holocaust. These men were assigned to cremate the remains of the victims who were killed in the gas chambers. This was a part of the Nazis' plan to eliminate Jewish people by working them to death or exterminating them.