The difference between a liquid and a gas is obvious under the conditions of temperature a
The fundamental similarity of liquids and gases becomes clearly apparent when the temperature and pressure are raised somewhat. Suppose a closed container partially filled with a liquid is heated. The liquid expands, or in other words becomes less denser some of it evaporates. In contrast, the vapor above the liquid surface becomes denser as the evaporated molecules are added to it. The combination of temperature and press at which the densities be come equal is called the critical point. Above the critical point the liquid and the gas can no longer be distinguished; there is a single, undifferentiated fluid phase of uniform. density.
Which of the following would be the most appropriate title for the passage?
A.The Properities of Gases and Liquids.
B.What Fluids and Gases Are Made of.
C.New Uses for the Gas and the Liquid.
D.New Theories about Fluids and Gases.