What is the author’s purpose in "The Thirsty Tree" in highlighting the various mistakes made by different agencies in the past? to suggest that the various agencies would do better if they were combined into one agency to oversee the entire region

to show the impossibility of managing the American Southwest environment without placing restrictions on human water usage

to show that efforts in the American Southwest need to focus on endangered wildlife as much as they focus on trees

to suggest a better approach to environmental management after showing how other strategies have ultimately been unsuccessful