what is the different in the book between loss and release? why do you think the author points out the distinction?

In both cases the person is dead. Release involves euthanasia or the killing of a person. The elderly or people who the Elders feel are unfit for the community is released. With Loss, the death is accidental. In such a tightly controlled environment, loss is rare yet it does happen. In the case of loss, a ceremony is performed where members repeat the person’s name until they pretty much forget him or her: then they give a newborn the person’s name.