In California, Pacific Northern rattlesnakes prey on California ground squirrels. Their relationship is a great example of coevolution. Read the Snake Venom Evolved to Kill Specific Squirrels with Shocking Precision article,then address the following questions:

Explain why the relationship between these two species is considered an example of coevolution.
What did you find most interesting or significant about how the rattlesnake population adapts to the squirrels defenses against its venom?