Well, they could tell because back then mostly only Jews were circumsised.
If you lived in Germany in the 2nd world war, then even being half Jewish could be enough. Children who's Grandparents or great Grandparents were persecuted.
He didn't plan to set up a Jewish state. He planned to kill all of the Jews he could get his hands on. He didn't just want Jews out of Germany, he wanted them out of the world.
There were not many things that the Jewish people in Germany could do during WWII, except keep their loved ones as safe as possible and try to flee Germany. The Jewish people could not sell their items, and it was extremely dangerous to buy anything else.
Hitler wanted to eradicate the whole of the Jewish population. He believed that Jews contaminated this world and so wanted to kill every Jew he could find.
They did the same activities as gentiles, with the difference that they followed their own religious practices. Those under German occupation were increasingly restricted in what they could do.
Most could not and did not hide, those that did; did so with the help of gentiles.
most did what they could whilst they could, some like Dr Miklos Nyiszli were given privellaged positions.
any that they could. Eventually most would have to use a boat or a ship, as there were few places of safety on mainland Europe.
Contrary to what is sometimes said, blond hair and blue eyes did not help ... If you were suspected of being Jewish you had to prove that you were Aryan (non-Jewish). In practice, this usually meant producing baptismal certificates for all four grandparents - or a really convincing explanation as to why you could not produce four certificates for them showing infant baptism.
German names are usually for people of German descent, and Jewish names are usually for people of Jewish descent. Many Jewish surnames originated in Germany and are shared by both Germans and Jews.
Just a few. How could anyone know accurately?
The Frank family celebrated Hanukkah in hiding because they were Jewish and practicing their religion openly could have put them at risk of being discovered by the Nazis during World War II. Celebrating Hanukkah in secret was a way to preserve their faith and traditions while trying to stay safe.