During which period did trees and ferns contribute to coal formation?

The correct response is based on the understanding of coal formation and the geological timeline. The Pennsylvanian Period, which is part of the Carboniferous Period, is specifically known for its extensive swamps and lush vegetation, including large trees and ferns. The conditions during this period were ideal for the accumulation of organic material, leading to the formation of extensive coal deposits.

During the Pennsylvanian Period, the Earth's climate was warm and humid, allowing for dense forests made up of tree ferns, seed ferns, and other primitive trees. As these plants died and accumulated in swampy areas, they were buried under sediment. Over millions of years, heat and pressure transformed this organic material into coal deposits that we mine today. The substantial presence of these plant types during this specific period is what primarily contributed to the formation of coal.

In contrast, while the Permian, Devonian, and Silurian periods saw the presence of plant life, they did not have the same combination of climatic conditions and abundant woody vegetation necessary for large-scale coal formation as observed in the Pennsylvanian Period. The Permian Period, for instance, saw the decline of the coal forests, and earlier periods like the Devonian and Sil