Final answer:
In medicine, a unit must maintain a written record of any deviation for a specific period of time.
Step-by-step explanation:
In the field of medicine, a unit must maintain a written record of any deviation for a certain period of time. According to the information provided, the FDA requires sponsors to report adverse drug events within specific timeframes. However, the specific duration for maintaining a copy of the written record of any deviation may vary depending on the regulations and policies of the unit or organization.