In which of these scenarios is informed consent of the study’s participants not necessary?

this protocol provides a detailed procedure for co-immunoprecipitation (co-ip) to identify protein–protein interactions.

not only is it colder, it also becomes darker, less salty, and more dense.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.