单项选择题 The heat required to change a substance from a solid to a liquid while at its freezing temperature, is known as the latent heat of （）.

单项选择题 With reference to a vessel’s structural integrity, the most significant characteristic of a cryogenic liquid is its （）.

单项选择题 The only means of removing the latent heat of condensation from a refrigerant in the normal refrigeration cycle is by （）.