Final answer:
The statement is false; high-voltage wires on towers are held by insulators, but they are not wrapped in insulating material; air acts as the insulator.
Step-by-step explanation:
False - The high-voltage wires you see on metal-frame towers are indeed held aloft by insulating connectors. However, they are not wrapped in an insulating material. Contrary to what might be assumed, these wires are bare and are insulated by the air around them. The insulating connectors prevent the electric current from traveling down the towers, while the significant separation from each wire and the ground ensures that the air insulation is adequate.