What tool is primarily used for gripping and turning nuts and bolts?

A wrench is the primary tool used for gripping and turning nuts and bolts because it is specifically designed to fit around the head of these fasteners. Wrenches have various designs, such as open-end, box-end, socket, and adjustable, which allow for better leverage and grip on different sizes of nuts and bolts. The design of a wrench enables the user to apply torque effectively, making it easier to tighten or loosen fasteners without slipping off, which can occur with other tools not intended for this purpose.

In contrast, a screwdriver is primarily used for driving screws and is not suitable for tensional applications like those required for nuts and bolts. Hammers are for striking objects and are not designed to grip or turn fasteners. A pry bar is meant for levering and prying rather than for handling nuts and bolts, making a wrench the most effective and appropriate tool for this task.