Why is social media so additive

Awaiver of the requirement for documentation of informed consent may be granted when: the investigator has no convenient place to store signed consent forms separate from the research datathe only record linking the subject and the research is the consent document and the principal risk is a breach of confidentiality.potential subjects might find some of the research questions embarrassing, personal, or intrusivethe subjects are literate in their own language; however, they do not read, write, or speak english

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

Why are the majority of the world's economies mixed? what may happen to the "pure" types of economies (traditional, socialist/command, market capitalist) when they incorporate elements from other economic models?