Which of the following is a characteristic of pneumatic systems?

Pneumatic systems utilize compressed air or gas as their working medium, which gives them the ability to operate effectively in a variety of environments, including low-temperature applications. Unlike hydraulic systems that use incompressible fluids, pneumatics can maintain their functionality in colder conditions where the properties of liquids might change. This characteristic makes pneumatic systems advantageous in settings where temperature variations are significant, allowing them to perform consistently without being hindered by the issues that liquids might face, such as freezing or viscosity changes.

In contrast, the other options do not accurately describe pneumatic systems. While they can sometimes be efficient, they are not universally more efficient than hydraulic systems in all scenarios. The statement about high power for heavy lifting typically pertains to hydraulic systems, which can lift heavier loads due to the incompressible nature of liquids. As for the use of incompressible fluids, this characteristic is specific to hydraulic systems rather than pneumatic ones. Thus, the ability to effectively function in low-temperature environments is a defining trait of pneumatic systems.