What is the difference between a giga coaster and a strata coaster

Aresearcher wants to do a web-based survey of college students to collect information about their sexual behavior and drug use. direct identifiers will not be collected; however, ip addresses may be present in the data set. risk of harm should be evaluated by: solely by the magnitude or severity of expected harm. both the magnitude (or severity) and the probability (or likelihood) of harm. solely by the probability of expected harm. neither the magnitude or probability of harm.