Correct Answer:Coaxial cable consists of a central metal core (often copper) surrounded by an insulator, a braided metal shielding, called braiding or shield, and an outer cover, called the sheath or jacket. The core may be constructed of one solid metal wire or several thin strands of metal wire. The core carries the electromagnetic signal, and the braided metal shielding acts as both a shield against noise and a ground for the signal. The insulator layer usually consists of a plastic material such as PVC (polyvinyl chloride) or Teflon. It protects the core from the metal shielding, because if the two made contact, the wire would short-circuit. The sheath, which protects the cable from physical damage, may be PVC or a more expensive, fire-resistant plastic.