If the mercury has become separated in a liquid-in-glass thermometer, what can be done to correct this situation?

Correct Answer: Option A — After removing the thermometer, hold the thermometer by the lower end and try to recombine the mercury by several full arm swings.

Separated mercury columns in liquid-in-glass thermometers can be rejoined by centrifugal force. Holding the thermometer by the lower end and swinging it allows the mercury to move toward the bulb, forcing the separated segments to recombine. This is a standard maintenance procedure for ensuring accurate temperature readings.