Respuesta :
Answer: Cenozoic era lasts for 56 million years. The animal group that was benefited significantly during the Cenozoic era was Mammals. The only category that can give birth to child is mammals. Cenozoic era is called the age of mammals because the largest land animal present at that time was mammals. The animals ruled over the era for many years and till date the animals which can give birth to the young ones are mammals
