C. growth of plants after a forest is destroyed by fire
Explanation:
When the ecological succession occurs on the land or region which was never inhabited by plants previously, the process is called primary succession. On the other hand, secondary succession occurs on land where the existing vegetation was destroyed by some disturbances. Secondary succession is a fast process compared to the primary succession as the soil is already present to support the growth of plants.
Among the given examples, the growth of plants after the vegetation of forest was destroyed by fire represents the process of secondary succession. Growth of vegetation on bare rocks, in the cracks in the concrete surface, or after the melting of glaciers represents the process of primary succession.
Answer: no body cavity—acoelomates; body cavity not completely lined with mesoderm—pseudocoelomates; body cavity completely lined with mesoderm—coelomates
