biology vs investigation

biology

noun
  • The study of all life or living matter. 

  • The structure, function, and behavior of an organism or type of organism. 

  • The living organisms of a particular region. 

investigation

noun
  • The act of investigating; the process of inquiring into or following up; research, especially patient or thorough inquiry or examination 

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