The vegetation in most environments is crucial as a food source for many animals in the area. Without it, many animals may starve, thus setting on a chain reaction of animal displacement.
We have a case of adaptability. Natural selection influenced by the environment selected which plant would do the best, In this case, A has adapted better than B.
This would be the organ. The order of all would be organelle, cell, tissue, organ, organ system, organism.
