What specific groups of people were targeted by the Nazis during the Holocaust?

Jews

Explanation:

The Nazi regime persecuted different groups on ideological grounds. Jews were the primary targets for systematic persecution and mass murder by the Nazis and their collaborators. Nazi policies also led to the brutalization and persecution of millions of others. Nazi policies towards all the victim groups were brutal, but not identical.

These people were targeted:

European Jews

European Roma (gypsies)

Homosexuals

People with disabilities

d. dr. francis collins

food chain i would say only because there is competition on getting food and survival