Which of the following best describes the function of calipers?

Calipers are precision instruments widely used in various fields such as engineering, manufacturing, and woodworking. Their primary function is to measure dimensions accurately and to assess the geometry of objects. They can measure the internal and external dimensions of objects as well as their depths, which is crucial when precision is required. Calipers can come in various forms, including digital, dial, or vernier types, each providing an accurate way to determine measurements down to millimeter or inch precision.

In the context of this question, measuring pressure and temperature, performing angular measurements, or calculating speed and acceleration falls outside the purpose of calipers. These tasks require different tools and instruments specifically designed for those measurements. Thus, the role of calipers is best captured by the option that focuses on measuring dimensions and geometry, distinguishing it clearly from the other functions mentioned.