Explanation should include sensors that measure

•    physiological signals 
•    biopotentials
•    biochemical signals.

Process/Skill Questions:

•    How are biosignals measured?
•    What are characteristics of good biosensors? What are the types of biosensors?
•    What are the specific challenges associated with measuring biosignals?
•    Why is it important to select the correct biosensor? What criteria are used to select the correct biosensor?
•    What are biopotentials?
•    What biosensors are currently commonly used [in research and healthcare]?
•    What limitations might there be with current biosensor technologies/mechanisms?