Describe how the dominant life forms changed during the mesozoic and cenozoic eras.

After the breakup of Pangaea early in the Mesozoic Era, reptiles were the dominant form of land animal. The first small dinosaurs appeared during the Triassic Period. Later, during the Jurassic and Cretaceous Periods larger dinosaur species evolved. Birds and mammals also appeared as the Mesozoic Era progressed. For most of the Mesozoic Era, gymnosperms were the dominant plant form. Angiosperms began to appear during the Cretaceous Period. After the mass extinction that marked the end of the Mesozoic Era, many life forms, including the dinosaurs, disappeared. Mammals became more prevalent, and angiosperms spread throughout the Cenozoic Era.

i believe the answer is three water molecules