Why did the Germans suffer starvation during World War I?
In WW1 Britain and Germany tried to starve each other into surrender by a naval blockade. In the longer run the British Navy was more successful at this ... Germany's agony was prolonged by its (for the time) modern and sophisticated chemical industry that enabled it to produce vast quantities of articial fertilizers, which raised the yield per hectare substantially. Without the work of Fritz Haber, Germany would probably have had to surrender much earlier.
How did Germans kill people during WWII? Well please keep in mind that not all Germans were Nazis. The Germans used the same weapons as did any of the other countries. The Nazis on the other hand used torture as a means of killing there victims. Starvation, burning, and experimentation were the main procedures used to kill the Jews, gypsies, and those they deemed unfit.
What did the Jews do that made the Germans lose the First World War which made the Germans build all those concentration camps which killed all those Jews?
the Jews did nothing wrong. its was just after the first world war and Germany was in a terrible state the NAZI party rose to power and Adolf Hitler blamed the Jews on the state of Germany. that is why the Germans built the concentration camps so they could make the Jews suffer how the Germans thought the Jews made their country suffer.