That depends what you want to measure about the room: for example its temperature, its color, etc.
Feet or meters
Degrees Celsius.
Metres most likely, or feet.
cm
grams which unit would you use to measure the mass of a mouse
Feet or meters
I would use meters.
Class room can be measure in Meters easily :)
Square feet is a good unit to measure the area of a room in a house.
Degrees Celsius.
Metres most likely, or feet.
division
Fahrenheit or Centigrade (Celsius)
cubic meters
The most appropriate measure is a metre.
The Unit Used To Measure A Train Can Be Kilometer.
best u nit to measure the length of bedroom = meter