The question is asking the determine the role that the United States do in the ecosystem base on the passage and situation in the question that you have state, base on my research, I would say that its role is a Dominant. I hope you are satisfied with my answer and feel free to ask for more if you have question and further clarification
It closely resembles gases
hopes this helps,
Xeno
I would say B because A doesn’t have a ring to it.
