Lactose intolerance is due to a(n): select one:
a. deficiency of lactase.
b. allergy to casein (milk protein).
c. deficiency of lactose.
d. deficiency of the gi flora (healthy bacteria

When a researcher debriefs her participants, she: provides a detailed explanation of the study. removes their undergarments. tells them they can stop taking part at any time. provides an detailed explanation of the study, and tells them they can stop taking part at any time.