Colten was created through the decomposition of

Coal was created through the decomposition of ancient trees.  Most of the coal was was formed 300 million years ago. At the time the earth was covered by swamps. When the ancient plants and trees died, their remains sank to the bottom of the those areas, making layers and layers of plant material and eventually forming a soggy, thick material called PEAT. Over time other materials covered the PEAT and due to pressure the PEAT turned to coal.

The answer is trees. As in ancient trees.

Colten was created through the decomposition of ancient trees.

Formation of coal begins in areas where groundwater is near or slightly above the topsoil. The plants, pieces of trees and dirt produce organic matter  quickly forming layers of organic matter that accumulates and gets buried. These layers of organic material form coal. The energy in coal comes from the Sun, and ends up being energy from sunlight trapped by dead plants.

answer; (d) one tectonic plate plunges beneath another; (most common,convergent boundaries)

answer; proximity;