Read the text "Space objects 'linked' to rise of mammals" and answer the question. Give short answers in no more than 2 words.
"Space objects 'linked to the rise of mammals"
Space impacts have had profound effects on Earth's ecosystems. For example, an asteroid which slammed into
Mexico's Yucatan Peninsula 66 million years ago was responsible for disappearing dinosaurs. The violent collision
caused fires, earthquakes and powerful tsunamis. According to geologists, clouds of dust and gas could cause
global cooling on Earth for several years, which made dinosaurs' disappearance faster. After the asteroid slam
the planet became essentially ice-free, with sea levels that were dramatically higher than now. Many small ocean-
bottom creatures became extinct.
A comet impact 55 million years ago may have helped mammals dominate the Earth. It could have activated a
quick phase of global warming linked to the growth of mammals. Released gases warmed the planet very quickly
55.6 million years ago. This spike in temperature is closely connected with growth of mammal groups in new
parts of the world. These mammals are divided into three groups that are still with us today. These three groups
are the Artiodactyla, the Perissodactyla and the Primates - the mammalian order that includes humans. Modern
Artiodactyls include sheep, pigs, camels and giraffes, while today's Perissodactyls include horses, tapirs, rhinos
and zebras. Scientists didn't completely understand how these mammals were divided.
All the information given so far is not conclusive, there is a lot of data to be investigated. Scientists' interpretation
remains controversial with other experts.
What is responsible for disappearing dinosaurs?​