Basically what we are looking at is the source of these. Vitamins are organic, that is they are carbon based molecules which are produced by other living things.
Minerals are inorganic and originally enter the biosphere primarily through plants.
Describe a negative feedback system associated with digestion. There were two discussed in class on Tues. The first dealt with the acidification of the stomach due to the stimulation of eating, and the role of the hormone gastrin.