Answer:
<em>The labels <u>I-VII</u> represent the different stages of primary succession. I-bare rocks, II-pioneers (mosses, lichen, algae, fungi), III-annual herbaceous plants, IV-perennial herbaceous plants and grasses, V-shrubs, VI-shade intolerant trees, VII-shade tolerant trees.</em>
I believe it is “animals and plants caanot directly use all the nitrogen found in our atmosphere”
Vestigial because they don't use it but it's still there
