What is a biogeographic realm? list eight of them. how do biogeographic realms indicate relatedness in terms of biodiversity at the global level?

Biogeographic realms refer to the huge spaces or regions on the surface of the Earth within which the development of ecosystems takes place. The animal and plant species witnessed in a biogeographic realm share identical features all the way through.  

The eight biogeographic realms are the afrotropical realm, Indomalayan realm, Antarctica realm, Neotropical realm, Nearctic realm, Palaearctic realm, Oceanian realm, and Australian realm.  

The biodiversity signifies the variability between the living species in every possible manner. Each of the biogeographic realm exhibiting identical environmental conditions or identical mediators of modification has been found to comprise an identical kind of biota.  

However, diversity can be found within it too. For example, the tropical moist rainforest found in any section of the globe will share identical procedures and vegetation, however, its specific structure will vary on the basis of the biogeographic realm in which it is witnessed.  

Analogous adaptation to the similar kind of environmental conditions between the distinct species of the distinct biogeographic realm can be witnessed at a global level.  

weathering is the answer.

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%