Please help According to the section "The Mountain Ranges of Europe and Asia," what are the natural barriers between Europe and Asia?

According to the federal regulations, which of the following studies meets the definition of research with human subjects? a. a researcher uses the customs office’s passenger lists for ships bringing immigrants to the us between 1820-1845 to track the numbers of immigrants from certain ethnic groups.b. a researcher conducts a linguistic study of comments posted on a local public blog.c. a developmental psychologist videotapes interactions between groups of toddlers and their care givers to determine which intervention methods most effectively manage aggression.d. a researcher asks the director of a local free clinic about the number of patients in the last two years with newly diagnosed hiv/aids.

During the 1500s,most rulers supported established a. political systems. d. none of the above b. churches c. freedom of speech

Many of these mythological stories were filled with violence. why do you think this is?