Which of the following did not occur during the cenozoic era?

a. advancing ice caps
b. climate change
c. volcanic out gassing
d. the formation of the ozone layer

Option d

Explanation: The formation of the ozone layer did not occurred during the Cenozoic era. It took place 2 million years ago. The formation of ozone layer took many years ago that still is present.

The ozone layer acts as a barrier and provides protection against the harmful radiation. The Cenozoic era started about 65 million years ago which proves the formation of ozone layer took long time ago and not during Cenozoic era.

i would have a lunch. it's one big package of food, making it one food. : p