Final answer:
The assertion that high-voltage wires are wrapped in an insulating material is false; rather, they are suspended by insulating connectors, and the surrounding air serves as a natural insulator.
Step-by-step explanation:
The statement that the high-voltage wires connected to tall metal-frame towers are wrapped in an insulating material is false. In reality, these high-voltage wires, often referred to as transmission lines, are usually not insulated. The reason they do not need insulation is that the air around them acts as a natural insulator. However, they are indeed held aloft by insulating connectors or insulators, which prevent the current from traveling down the towers to the ground, which would short-circuit the line. The main purpose of these insulators is to support the weight of the lines and to keep them isolated from the towers and the ground, ensuring safe and effective transfer of electricity. Adequate separation between power lines and to the ground, provided by these towers, is sufficient to prevent arcing and keep the system safe.