text: A benign Warthin tumor may form in a structure that produces this substance.
full_question: A benign Warthin tumor may form in a structure that produces this substance. An elevated level ofcortisol in this substance at midnight indicates Cushing's syndrome. The painkiller opiorphin was isolatedfrom this substance. Its production decreases in xerostomia. The bird genus Aerodramus, which lives inrural China, creates its nests out of this substance. HHV-6, the causative agent of roseola, is transmittedsolely through this substance, and (*) mononucleosis gets its nickname from being transmitted in it. Thesubmandibular, sublingual, and parotid glands secrete this liquid, which transforms food into a bolus and begins theprocess of digesting starch. For 10 points, name this mostly watery liquid found in the mouths of humans.
first_sentence: A benign Warthin tumor may form in a structure that produces this substance.
raw_answer: saliva [prompt on spittle]