So you know how it fits together, the ordering of the sequence.
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>
