You work as an epidemiologist for the Maryland Health Department. A colleague asks for your help creating a surveillance system to track deaths from the ongoing opioid epidemic. You suggest that the surveillance system require all local clinicians to report deaths due to drug overdose. Based on this description only, this surveillance system is an example of: a. Passive surveillance b. Active surveillance c. Sentinel surveillance 8. Which of the following is not a characteristic of a cross-sectional study? a. Unable to establish the sequence of exposure and outcome b. Can be conducted in less time and with less money than many other study types c. Typically used to generate hypotheses, rather than to establish causal relationships d. Possibility of recall bias is eliminated because data on exposures are obtained before disease develops.