The Mesozoic Era is not part of the Paleozoic Era. It is the era that follows the Paleozoic Era and lasted from about 252 mya to 66 mya.

Fish were the first major group of animals to evolve during the Paleozoic Era. They appeared in the Cambrian Period and quickly diversified into a wide variety of forms.

The extinction of the dinosaurs occurred at the end of the Mesozoic Era, not the Paleozoic Era.

The climate during the Paleozoic Era was generally warm and humid. This was due to the high levels of carbon dioxide in the atmosphere, which trapped heat and kept the Earth's temperature warm.

The extinction of the dinosaurs occurred at the end of the Mesozoic Era, not the Paleozoic Era.

Arthropleura was a giant millipede that lived during the Carboniferous Period. It was the largest land animal of the Paleozoic Era, reaching lengths of up to 2.6 meters (8.5 feet).

Angiosperms, or flowering plants, did not evolve until the Cretaceous Period of the Mesozoic Era.

Trilobites were a group of marine arthropods that were very common during the Paleozoic Era. They ranged in size from a few millimeters to over 2 meters (6.5 feet) in length.

The Triassic-Jurassic extinction event occurred at the end of the Triassic Period, not the Paleozoic Era.

Pangea was a supercontinent that formed during the Paleozoic Era. It was made up of all of the Earth's landmasses and existed from about 335 mya to 175 mya.

Uranium is not a type of Paleozoic fossil fuel. It is a radioactive element that is used in nuclear power plants.

The Ordovician-Silurian extinction event was the first mass extinction event that occurred during the Paleozoic Era. It happened about 444 mya and wiped out about 85% of all marine species.

The rise of the dinosaurs occurred during the Triassic Period, not the Permian Period.

The Permian Period was the last period of the Paleozoic Era. It lasted from about 299 mya to 252 mya.

Birds evolved during the Mesozoic Era, not the Paleozoic Era.