Problem 22
Form Hypotheses Suggest some reasons why trilobites might have become extinct at the end of the Paleozoic Era.
Problem 23
Why might mammals in Australia be so much different than mammals on other continents?
Problem 24
Describe how natural selection might cause a species to change through time.
Problem 26
Make a Display Certain groups of animals have dominated the land throughout geologic time. Use your textbook and other references to discover some of the dominant species of each era. Make a display that illustrates some animals from each era. Be sure to include appropriate habitats.
Problem 26
What are mass extinctions? How have they affected life on Earth?
Problem 27
Write a description of what Earth was like during Precambrian time. Summarize how Earth was different than it is now.
Problem 28
Interpret Data The Cenozoic Era has lasted 65 million years. What percentage of Earth's \(4.5\)-billion-year history is that?
