So, on what finger do you wear a promise ring? In the USA and the UK, the ring finger (fourth finger) of the left hand holds the greatest significance; engagement rings and wedding rings are worn on this finger almost without exception.
In biology and ecology, extinction is the end of an organism or of a group of organisms (taxon), normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively.
Scientists define a mass extinction as a period of less than two million years in which at least 75 percent of species go extinct. Itâs the End of the World but Weâll Be Fine Nick Romeo May 17, 2013. The Medean world is one out of balance, where over competition leads to mass extinction.