Final answer:
The statement about high-voltage wires being wrapped in insulating material is false; they are held by insulating connectors but are not wrapped in any material, as the air serves as the insulator.
Step-by-step explanation:
The statement that high-voltage wires connected to tall metal-frame towers are held aloft by insulating connectors, and these wires are wrapped in an insulating material is false. In reality, the high-voltage wires, also known as transmission lines, are indeed held up by insulating connectors; however, they are not wrapped in insulating material. The air around the wires serves as a natural insulator, and therefore, additional insulation on the wires themselves is not necessary for the high voltages they conduct.