What were the main occupatiants of early africans

Sam and ben have discovered some strange animals living in the woods behind their house. ben is excited because he believes they are marsupials, an animal he's never observed in the wild before. his brother is sure it is not. what feature should the boys consider in deciding whether the animals are marsupials?

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.

Which groups of people most directly benefited from song innovations in the song dynasty‘s open border policy?