Coral reefs are a magnificent creation of earth. When you come in contact with a coral reef you experience a sense of pleasure that you've never experienced before. The beauty of these coral reefs leaves you awestruck and flabbergasted. Coral reefs produce an income by creating a tourist attraction which generates mulllla.
The reticular formation can be said to be a network of nuclei in the brainstem that wakes or alert us to a sharp reaction or occurence at a particular time.
You take any of the "signs of change in populations of organisms and their environments". For imagine, Australopithecus (early man) turning to Homo sapiens. In that way they could tell that you took this journey.