preservation vs uncertainty

preservation

noun
  • The act of preserving; care to preserve; act of keeping from destruction, decay or any ill. 

  • The state of being preserved, how something has survived. 

uncertainty

noun
  • Doubt; the condition of being uncertain or without conviction. 

  • A parameter that measures the dispersion of a range of measured values. 

  • Something uncertain or ambiguous. 

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