fitness vs senescence

fitness

noun
  • The condition of being attractive, fanciable or beautiful. 

  • The cultivation of an attractive and/or healthy physique. 

  • The condition of being fit, suitable or appropriate. 

  • An organism's or species' degree of success in finding a mate and producing offspring. 

senescence

noun
  • Old age; accumulated damage to macromolecules, cells, tissues and organs with the passage of time. 

  • The state or process of ageing, especially in humans; old age. 

  • Fruit senescence, leading to ripening of fruit. 

  • Ceasing to divide by mitosis because of shortening of telomeres or excessive DNA damage. 

  • Condition when the cell ceases to divide. 

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