behave vs observe

behave

verb
  • To conduct (oneself) well, or in a given way. 

  • To act in a polite or proper way. 

  • To act, conduct oneself in a specific manner; used with an adverbial of manner. 

observe

verb
  • To follow or obey the custom, practice, or rules (especially of a religion). 

  • To take note of and celebrate (a holiday or similar occurrence); to follow (a type of time or calendar reckoning). 

  • To notice or view, especially carefully or with attention to detail. 

  • To comment on something; to make an observation. 

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