GEOLOGY

Detailed explanation-1: -During this era all major invertebrates appeared along with fishes and amphibians. But the animal that dominated the Paleozoic era was mostly fishes.

Detailed explanation-2: -The Paleozoic Era ended with the largest extinction event of the Phanerozoic Eon, the Permian–Triassic extinction event. The effects of this catastrophe were so devastating that it took life on land 30 million years into the Mesozoic Era to recover. Recovery of life in the sea may have been much faster.

Detailed explanation-3: -Paleozoic (541-252 million years ago) means ‘ancient life. ‘ The oldest animals on Earth appeared just before the start of this era in the Ediacaran Period, but scientists had not yet discovered them when the geologic timescale was made.