Which tool is most suitable for clamping wood together?

The hand screw clamp is most suitable for clamping wood together because it is specifically designed for this purpose. It consists of two wooden jaws connected by a threaded screw mechanism, allowing for firm and adjustable pressure to hold wood pieces tightly in place. This makes it ideal for gluing joints or holding materials steady while performing tasks like drilling or cutting.

The other tools listed are meant for different functions. Hedge shears are designed for pruning plants and landscaping, not for clamping wood. A grease gun is used for applying lubricants, which is unrelated to woodwork tasks. A hack saw is intended for cutting metal or plastic, and while it may occasionally be used in wood projects, it doesn't serve the function of clamping. Thus, the hand screw clamp is the clear choice for securely holding wood pieces together during work.