Final answer:
Underwater cable networks consist of optical fiber cables or coaxial cables that transmit signals for telephone conversations, internet communications, and submarine communication systems. These cables are laid on the ocean floor and provide advantages such as low loss, high bandwidth, and reduced crosstalk. Submerged submarines use extremely low frequency (ELF) radio waves to communicate.
Step-by-step explanation:
Underwater cable networks are used to transmit signals for telephone conversations, internet communications, and submarine communication systems. These networks consist of optical fiber cables or coaxial cables that are laid on the ocean floor. Optical fibers offer advantages such as low loss, high bandwidth, and reduced crosstalk, making them suitable for long-distance communications. Submerged submarines, on the other hand, use extremely low frequency (ELF) radio waves to communicate, as these waves can penetrate salt water.