Answer:
D). Various agencies have implemented plans that were not based on good evidence or a holistic view of the ecosystem.
Step-by-step explanation:
The last statement most adequately narrates the author's stand in the text 'The Thirsty Tree.' It reveals the author's outlook on different agencies' inadequate enactment of the plans because he believes that these plans lacked sufficient backing evidence and an integrated approach towards the ecosystem that could be applied everywhere. This affects the efficacy of the plans and prevents them from achieving the intended goals with which they were made and implemented. Thus, option D is the correct answer.