Question

what global event occured before the appearance of complex life?
o a the cambrean explosion
o b snowball earth
o c the rise of mammals
o d the extinction of dinosaurs

question 15 (1 point)
which event marks the sudden appearance of many complex animal forms?
o a the oxygenation of the atmosphere
o b the cambrian explosion
o c the triassic period
o d the rise of mammals

Explanation:

For the first question, Snowball Earth occurred before the appearance of complex life. The Cambrian explosion marks the sudden appearance of complex life. The rise of mammals and extinction of dinosaurs happened much later. For the second question, the Cambrian explosion is known for the sudden appearance of many complex animal forms. The oxygenation of the atmosphere predated the Cambrian explosion and was a long - term process, the Triassic period was more about the rise of dinosaurs after the Permian - Triassic extinction event, and the rise of mammals occurred after the extinction of dinosaurs.

Answer:

Question 14: B. snowball earth
Question 15: B. The Cambrian Explosion