The correct answer is Mesozoic (middle life)
Step-by-step explanation:
The Phanerozoic Eon is the geological eon we are in, which began 543 million years ago to nowadays, this eon includes three different eras, the first one is the Paleozoic or ancient life in which fish, reptiles and amphibians dominated; the second is the Mesozoic or middle life in which there were reptiles (dinosaurs) dominated and mammals and bird evolved and the Cenozoic (recent life) which is the era we are in mainly dominated by mammals and in the last years humans. The name Mesozoic derives from Grees as in Greek meso means between and zoic is animal or life, thus the geological period between the Paleozoic and the Cenozoic is the Mesozoic.