Which tool is primarily used to mark lines for cutting wood?

The tool primarily used to mark lines for cutting wood is a chalk line. A chalk line allows carpenters and woodworkers to create long, straight lines on wood or other materials, which are essential for making accurate cuts. To use a chalk line, a chalk-filled string is stretched taut between two points and then snapped, leaving a visible chalk line on the surface. This is particularly useful for large sheets of wood or for marking cuts over longer distances where a straight edge or ruler may not suffice.

While chisels are more suited for carving and shaping wood, measuring tapes are used primarily for determining lengths and distances, and hammers are intended for driving nails or joining pieces of wood rather than marking. Thus, the function of a chalk line closely aligns with the task of marking accurate cutting lines, making it the most appropriate choice in this context.