What is a straight edge commonly used for?

A straight edge is primarily used for making precise measurements and ensuring straight lines in various applications such as drawing, drafting, and construction. It serves as a reference line for measuring and cutting materials, ensuring accuracy in alignment and dimensions.

Although a straight edge can indirectly assist with leveling surfaces by providing a straight reference line against which to measure or align other tools (like a level or ruler), its primary function is not to level surfaces directly. Similarly, it does not measure temperature, and it is not used for testing electricity, as those functions require different specialized tools. The focus of the straight edge on precision makes it an essential tool in technical and engineering tasks, which distinguishes it as the correct choice.