The carbon atom has unique properties that allow it to form covalent bonds to as many as four different atoms, making this versatile element ideal to serve as the basic structural component, or “backbone,” of the macromolecules.
Answer:
Pb has an atomic mass of 82. If an atom of that element has an atomic mass of 80, that atom is known as: an isotope.
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