Today, Scientists Believe That the Main Reason the Earth Has

Multiple Choice

Today, scientists believe that the main reason the Earth has had periodic ice ages is:

A) slow changes in the tilt of our planet's axis of rotation
B) the grinding of continental plates against each other over the centuries
C) changes in the composition of the Earth's atmosphere that affect the ozone layer
D) the fact that the Moon is slowly moving toward the Earth and drawing off heat
E) no one has any good theories about the cause of the ice ages
Section 8.4: Life, Chemical Evolution, and Climate Change