If you mean victims when you say 'involved' the key groups were:
The main effect was six million less people were living.
the Jews were the main people killed in the holocaust. some gypsies were killed but mainly the Jews
Yes, that was the main part of the Holocaust.
The main victims of the Holocaust were people of the Jewish religion. There were other victims, but the Natzis were mainly focused on the Jewish religion when the Holocaust began.
The driving force behind the Holocaust was Hitler, gleefully assisted by Himmler and the rest of the Nazi leadership.
The main effect was six million less people were living.
the Jews were the main people killed in the holocaust. some gypsies were killed but mainly the Jews
Yes, that was the main part of the Holocaust.
the Holocaust was not a movement or a party or anything with members that could have a leader, it was an event. Within the Holocaust there were three main sides, on each of those sides there were many leaders.
The main victims of the Holocaust were people of the Jewish religion. There were other victims, but the Natzis were mainly focused on the Jewish religion when the Holocaust began.
The driving force behind the Holocaust was Hitler, gleefully assisted by Himmler and the rest of the Nazi leadership.
Jews, Gypsies, and mentally/physically deformed people.
This is a very subjective question and there will be many opinions, for me; the most important fact about the Holocaust is that different places/people will use the Holocaust to promote their own ends. To find out the truth it is best to go to the centre; Yad Vashem is the main and best source for the Holocaust.
The Holocaust is a concept, it did not have the ability to attack.
This is a very tricky answer. One of the main were Jews. Other hiders of Jews and helping them escape. Some were people who tried to fight anyone pro holocaust. Some twins were taken for experimental reasons
the main tragedy people are aware of in the holocaust, many jews were killed in them
People who do not believe that the holocaust took place are known as 'holocaust deniers.'