Fact 1: The number of rings in a tree trunk can be used to estimate the age of the tree.

Fact 2: Tree-ring dating the 1700 Cascadia earthquake.

Given the two facts above, answer the question "Estimating the age of trees can be used for what" with the following options: 
- genetic diversity
 - they body they live in
 - earthquake history
 - food and shelter
 - gardening
 - important habitats
 - bird watching
 - recreation


 

   earthquake history      