One of the oldest known mammalian fossils belongs to a small…
Questions
One оf the оldest knоwn mаmmаliаn fossils belongs to a small furry species, Hadrocodium wui, that lived 195 million years ago. For the following 100 million years, only a small number of groups of mammalian fossils are found in the fossil record. By 65 million years ago, the non-avian dinosaurs were extinct. By 55 million years ago, there were 130 mammal genera, including 4,000 different species that occupied a wide variety of habitats. Which of the following best describes the cause of the rapid increase in the number of mammalian species between 65 and 55 million years ago?