Source 144: The following quote comes from the Merriam-Webster website; accessed Dec.18 2014 at: http://www.merriam-webster.com. This link may or may not still be operational; if it isn't, we may have redirected it to the WayBackMachine archive.
‘a largely inheritable and unalterable tendency of an organism to make a complex and specific response to environmental stimuli without involving reason’
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