Which era is associated with the formation of the Appalachian Mountains and the age of amphibians and fish?

• A. Cambrian Era
• B. Paleozoic Era
• C. Precambrian Era
• D. Mesozoic Era

Answer: (B)

During the Paleozoic Era, two major threads run together: the building of the Appalachian Mountains from the collision that formed the supercontinent Pangaea, and the rise and diversification of early vertebrates like fishes and amphibians. The Devonian period within this era is famous as the “age of fishes,” while amphibians became well established on land later in the Paleozoic. The other eras don’t fit: Precambrian and Cambrian are far too early for large mountain-building and wide vertebrate diversification, and the Mesozoic comes after the Paleozoic, known for dinosaurs rather than the early Appalachian formation and early amphibians.