During the Cenozoic Era the global climate has turned colder, with the ice caps returning to North America, Eurasia, and Antarctica.
All continents extensively developed rocks, particularly on lowland plains such as the Gulf and Atlantic coastal plains of North
America. This time in Earth's history marks the disappearance of the dinosaurs.
What is true about life on Earth at this time?
flowering plants appeared
non-vertebrates dominated
fish emerged during this time
small animals diversify quickly

The appearance of the Cenozoic period took place with the vanishing of the dinosaurs, this scenario is nearly 65 million years earlier, which is continued till today. This era has been splited into two periods of time named as the Tertiary and the Quaternary. There were inevitably number of vacant spaces on Planet where animals could survive after the dinosaurs' absence.

Immediately after their extinction, several vacant areas have been studied in nature where animals could flourish. At the start of the Cenozoic the mammals which were small, mouse resembling animals getting scattered rapidly and also diversified quickly in nature, their size also started increasing. Massive elephants and rhinos, sabre-tooth cats and lions, horses and deers quickly got populated in Earth's plains and forests.