Although I don't know the answer to the first question, I do know that oysters are able to change their gender. For other species, I don't exactly know how they reproduce with the same gender. But I hoped this still helped a bit!
Answer: His experience as a Holocaust survivor.
Explanation:
Elie Wiesel is a survivor of Auschwitz who wrote about his experience in a short memoir titled Night. He was awarded the Nobel Peace Prize because of his chronicles about the Holocaust and his fervent work on recovering those kinds of stories. The ‘kingdom of night’ is a reference to the awful events of the Holocaust.
You can tell that friend that it's better not to get stressed out and to always sustain positive relationships with everyone, having negative relationships is not good for everyone and can bring effects to us.