Why does water boil at a temperature below 100 degree Celsius at higher altitudes?

Normal temperature of human body on Celsius scale will be (in degree)

At which temperature does liquid water show maximum density ?

At which temperature, the celsius and Fahrenheit scales coincides?

The amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius is called its:

The density of water will reach its maximum value at the temperature of –