By the ________ period, large tropical swamps extended across North America, eventually becoming the vast coal deposits of today.
A) Cambrian
B) Silurian
C) Pennsylvanian
D) Devonian
E) Triassic

Question

Quizplus · Accepted Answer

The Pennsylvanian period, which occurred between 323 and 299 million years ago, is known for its extensive coal-forming swamps that covered much of North America. The other answer choices are incorrect because they either predate or postdate the Pennsylvanian period and do not correspond to the development of large tropical swamps.

By the ________ Period, Large Tropical Swamps Extended Across North