They dont release any oil
they "preen" their feathers with their beaks not put oil on them
<span>Antrophocentric ideas and beliefs involve believing that only human beings and human beings alone are of the utmost importance above all else, that the human self is of the total concern. It is a very "self" oriented set of ideas. Eccocentrists are particularly and primarily focused on the environment, preservation, and "green" movements.</span>
A frog gets rid of it's urine through the kidneys because the heart pumps blood throughout the body, the lungs are used to take in O2 molecules and gills are use to filter out the hydrogen in HO2 so they can breathe under water. However the kidneys are part of the waste disposal system (what makes us need trip to the bathroom ever now and then) therefore that is the answer.<span />
Before your food passes from the mouth and down your esophagus, salivary amylase, an enzyme in saliva, begins to digest the starch in your bread. That is the start of chemical digestion. ... The passage of the bolus through the esophagus to the stomach occurs by peristalsis, a series of wave-like muscle contractions.
Minerals would be a reasonable explanation to this scenario
My opinion is on Minerals
Answer=Minerals
