What characterizes liquefied compressed gases?

Liquefied compressed gases are specifically characterized by their ability to exist in a liquid state when subjected to certain pressure conditions, typically at standard temperature and pressure levels. This characteristic is essential in various applications, including the medical field, where gases such as oxygen and nitrous oxide are stored and transported in a liquid form for efficiency.

Under higher pressure, these gases can condense into a liquid, allowing for a denser and more manageable form for storage and use. When the pressure is released, these gases revert to their gaseous state, which is fundamental to their function in medical settings.

Other options do not accurately describe liquefied compressed gases. Some may be too vague or incomplete, while others misrepresent the nature of these gases at standard conditions. Thus, the focus on pressure conditions as a determinant factor for liquefaction is what makes the selected answer the most accurate.