[问答题]
The following diagramb-cg .ep,jj7bh*rx6bk 4omd d,4(lu t shsy6sqvhd5 -*0z o;pp iows a trophic level pyramid of energy.
1.Label the bottom (step A) and topmost steps (step D) of the pyramid to describe what types of organisms are present in the two levels.
2.State which trophic level can support the largest population of people, step A or step B?
3.Explain why animals at level D are most vulnerable to becoming extinct.
