As we all know, the earth is tightly wrapped around a layer of atmosphere. check here .From the ground up, it can be divided into five layers from bottom to top: troposphere, stratosphere, intermediate layer, ionosphere and dissipation layer. The troposphere closest to the ground is the closest to humans, bringing complex weather phenomena such as clouds, rain, fog, wind, frost, snow, etc.; and the stratosphere above the troposphere has an ozone layer with a concentration of 10% and a thickness of 30 kilometers, it can absorb a lot of radiation from the universe, especially to absorb 99% of the sun's ultraviolet radiation to the earth, so that the creatures on the earth are protected from harm. Therefore, the ozone layer is known as the "protective umbrella of human beings". If this "protective umbrella" is lost, the earth will be strongly radiated by ultraviolet rays, species will be difficult to survive, and human health will be greatly threatened. This is not a sensation, but a fact, and ominous signs have emerged in many places. Such as the ground creatures under the Antarctic ozone hole. In the area bordering the Strait of Magellan on the southern tip of Chile, there are many active and active fish in the river. Today it has become a "blind fish" in which the trees are smashed; the flocks who like to wander have become "blind sheep" due to cataracts... Who is the murderer? For nearly half a century, due to the development of industry, more and more widely used chlorofluorocarbons with relatively stable nature, non-flammable, easy to store, and relatively inexpensive are used as refrigerants, sprays, foaming agent and cleaning agent. These substances can exist in the atmosphere for a long time and destroy the ozone layer, that is, they endanger the health of human beings and affect the growth of living things.
Organ transplantation was once a complex and dangerous operation that was only performed when it was unavoidable. With the continuous improvement of medical standards, the transplantation of internal organs such as the heart and kidneys is commonplace today, and we will soon be familiar with the transplantation of hands, knees, ears and even faces. In January 1999, Australian and American doctors performed hand transplants and succeeded. The nerves, blood vessels, muscles and bones of the hand are very complex. The success of these two procedures marks that the transplantation technology has developed to a considerable height. But the transplant technology won not only cheers.
In a novel, a science fiction writer wrote that an irresponsible scientist who used pieces of corpse to piece together a non-human and non-beast monster, causing many people's doubts about organ transplant surgery. Who is legally a person who has undergone a head transplant? Is the provider of the head or the provider of the body? It goes without saying that a limit should be set for organ transplantation. But where should this boundary be? This is a question that many ethicists are considering.check here