Which of the following helps determine past climate on the basis of tree rings?
A) Dendrochronology
B) Oxygen isotope analysis
C) Pollen analysis
D) 18O/16O ratio
Question 2
As a whole, over the past 70 million years there has been ________.
A) a global cooling
B) a global warming
C) a global warming and then a global cooling
D) no significant climate changes
E) no way to determine if there have been climate changes