Approximately what percentage of Rb-87 will remain in the rock when it is 2 billion years
Old?

Aresearcher proposes to conduct a study at a foreign site. the research has been determined to be exempt from the federal regulations by institutional policy. according to federal regulations, is review required at the foreign site? if a proposed study qualifies for exemption, federal regulations do not require review at the foreign site where it will be conducted but still require review at the u. s. site by the institution’s irb. if a proposed study qualifies for exemption, federal regulations do not require review at the foreign site where it will be conducted. if a proposed study qualifies for exemption, federal regulations do require review at the foreign site where it will be conducted. if a proposed study qualifies for exemption, federal regulations do not require review at the foreign site where it will be conducted, but still require review by the institutional official at the local site.

Why is it difficult to determine which countries belong to europe and which belong to southwest asia

Which factor contributed to the rise of african empires such as ghana and mali ? a. their creation and involvement in trade networks b. they focused only on agricultural production. c. they didn’t engage in warfare with other nations d. their geographic location protected them from attacks.