Which type of primary research typically requires no direct involvement with human subject?

How has our understanding of the first sentence of the declaration of independence changed over time?

Occurs with the fully informed request of a competant adult patient or their surrogate. culture of life: select the best answer from the choices provided. a. voluntary euthanasia b. nonvoluntary euthanasia c. involuntary euthanasia d. passive euthanasia

Acase study allows a more detailed look at the life of a single subject than any other study