A、Because it is more accurate than the Celsius scale. B、Because it is easier to use. C、Because it is convenient for measuring th

It is difficult to give an accurate definition of "temperature", but we can try. Temperature is not the total amount of heat in a thing but the intensity of its heat at a certain time. When we measure temperature we do not measure the quantity of heat but its intensity. A large pan of boiling water obviously contains more heat than a smaller pan of boiling water, but their temperatures arc the same. The water in both pans has a temperature of 100 degrees Celsius.
    To measure temperature accurately we need good instruments. The accuracy of a measurement depends partly on the instrument, which is used.  Most instruments used to measure temperature are called thermometers. In measure thermometers two scales are used, the Fahrenheit scale and the Celsius scale. American doctors find the Fahrenheit scale convenient for measuring the temperature of the body, but other doctors and scientists often use the Celsius scale. The boiling points of water are different on the two scales. On the Celsius scale, water boils at 100 degrees. On the Fahrenheit scale it boils at 212 degrees.