biosphere vs terrain

biosphere

noun
  • The part of the Earth and its atmosphere capable of supporting life. 

  • The totality of living organisms and their environment. 

terrain

noun
  • The surface of the earth; the ground. 

  • A single, distinctive rock formation; an area having a preponderance of a particular rock or group of rocks. 

  • An area of land or the particular features of it. 

How often have the words biosphere and terrain occurred in a corpus of books? (source: Google Ngram Viewer )