What device serves as a safety feature by melting when too much current passes through a circuit?

The correct answer is the fuse, which is a critical safety device used in electrical circuits. A fuse is designed to protect the circuit from overloads by melting a wire or a strip of metal inside it when the current exceeds a certain level. This melting breaks the circuit and stops the flow of electricity, thereby preventing potential damage to the electrical system or the risk of fire.

In contrast, a transformer is used to change the voltage levels in an electrical circuit but does not provide overcurrent protection. A service drop refers to the overhead or underground cables that deliver electricity from the utility to a home or building and does not function as a protective device. A Ground Fault Circuit Interrupter (GFCI) is designed to protect people from electrical shock by sensing imbalances in the current and disconnecting the power, but it does not operate by melting under excessive current conditions.