Under which circumstance might you receive a tax refund from the irs?

In the mid 1800s western settlers and american indians differed in their views about

As our current atmosphere formed, the concentrations of various atmospheric gases fluctuated. match each gas with the explanation that best describes how its proportion changed during the evolution of the atmosphere.

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