Final answer:
The computer is considered the "lifeline" of the Medical Office as it is essential for tasks such as medical record-keeping, scheduling appointments, managing patient information, and conducting research.
Step-by-step explanation:
The piece of equipment that is considered the "lifeline" of the Medical Office is the computer. Computers are essential for medical record-keeping, scheduling appointments, managing patient information, and conducting research. They enable healthcare professionals to access and analyze patient data efficiently, communicate with other healthcare providers, and perform various administrative tasks.