Which type of cables are used for high-capacity trunk lines that provide main routes for telephone, cable, and internet communications?

Fiber-optic cable

Explanation:

Before the cable industry transitioned to fiber-optic cables, for many years, the standard cables used for telephone, cable, and internet communications were coaxial cables. The transition was made possible because the architecture of the fiber-optic cable came with a higher capacity, more extensive bandwidth link. Unlike the coaxial or the twisted pair cable, the fiber-optic is made from glass strands that transmit light signals much quicker and to greater distances. This makes fiber-optic cables the fastest high capacity data transfer link than any other cables to ever exist.