Extension lines on a technical drawing define size or what other element?

Extension lines are crucial elements in technical drawings that help convey specific measurements and their locations. These lines extend from the edges of the feature being dimensioned and indicate where a measurement begins and ends, effectively defining the size of that feature in relation to its position on the drawing.

In this context, the correct answer emphasizes that extension lines are not only about the size of an object but also illustrate the location of that size on the drawing. Location is critical because it provides context, ensuring that anyone interpreting the drawing understands exactly how the defined measurements relate to the overall design.

The other choices do not align with the primary purpose of extension lines. For example, color, material, and weight are attributes that can be represented in other ways on a drawing but are not defined by extension lines, which focus specifically on indicating size and location.