An_______ species of organisms is unique to a specific environment and not found in other areas A) endemic B) adapted C) abiotic D)biotic. 2. The protective layer of special oxygen molecules in the upper stratosphere that screens out much of the harmful radiation from the sun A) atmosphere B) adapted C) ozone D) biosphere

Endemic species are species that occur exclusively in a specific geographic region. The opposite of endemism is cosmopolitanism, a condition in which a species is widely distributed throughout the world, which is quite rare, since most species are restricted to a geographical region, whether broad or not. A species can be endemic to a continent, a country, an island or any other specific region.

The ozone layer is composed of ozone gas (whose molecular formula is O3) and is located in a region of the atmosphere called the stratosphere, which is between 20 km and 35 km from the Earth's surface. The existence of the ozone layer helps to maintain life on our planet, since it can filter about 95% of the ultraviolet (UV) rays coming from the Sun, preventing most of these rays from reaching the Earth's surface.