biology vs physiology

biology

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

  • The study of all life or living matter. 

  • The living organisms of a particular region. 

physiology

noun
  • A branch of biology that deals with the functions and activities of life or of living matter (as organs, tissues, or cells) and of the physical and chemical phenomena involved. 

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