____________. ??? ??? ??? water The most abundant substance in the body. ??? ??? ??? GI Tract The mouth, esophagus, stomach and intestines make up the ________. ??? ??? ??? accessory organs The liver, pancreas and gall bladder are ________ to the digestive system. ??? ??? ??? absorption The primary function of the small intestine is ____________. ??? ??? ??? speeds up A stimulant is a drug that __