Final answer:
Blades #11 and #12 fit into a knife handle made of various materials such as wood, bone, metal, or plastic, depending on the design and purpose of the knife.
Step-by-step explanation:
Blades #11 and #12 fit into a knife handle. The specific type of knife handle depends on the design and purpose of the knife. In the field of arts, knife handles can be made from various materials such as wood, bone, metal, or even plastic. The design of the handle provides a comfortable grip and allows the blade to be securely attached.