A clinical thermometer is different from other mercury in glass thermometers owing to
-
the constriction on its stem
- the grade of mercury used in it
- its long stem
- its wide range of temperatures
The correct answer is: A
Explanation
The constriction in the stem of a clinical thermometer prevents the mercury from returning to the bulb after the temperature has been taken, allowing for a more accurate reading. This feature is what distinguishes it from other types of mercury thermometers, which do not typically have this constriction