Feet.
You would use the unit of measurement "centimeters" or "inches" to measure your classmate's height.
To measure the height of your school, you would typically use meters, as it is the standard unit of measurement for height in the metric system. For smaller measurements, centimeters could also be used, but meters would provide a clearer understanding of the overall height.
It depends on what characteristic you want to measure! Its mass, its height, the amount of body fat, the fineness of its fleece?
Feet or metres would seem the most suitable.
Centimetres.
Glass of water
The metric unit commonly used to measure height is the meter. So, you would measure the height of Big Ben in meters.
Centimetres.
metres
A door is about 2 meters, but most likely you'd measure in centimeters.
a centimeter
You define the height of the object as one unit and then, to measure anything else, you count how many times larger than the unit it is.