(E)Our internal senses keep us alive and enable us to use our external senses. In effect, the internal senses tell our brains how to runour bodies. Hunger and thirst register in a part of the brain called the hypothalamus when a lack of food chemicals is detected in theblood.    Another internal sense that controls our balance is maintained by three fluid-filled loops in the inner ear. Changes in position andgravity affect the motion of this liquid and trigger changes in the brain. A sense called kinesthesia lets us know the relative positionsof parts of our bodies. Even our breathing is trigg ered by a sense that identifies an overabundance of carbon dioxide and lack ofoxygen in the blood. 54. We feel hungry because
(A) our brain makes us think about food all the time.
(B) our brain senses a change of gravity.
(C) we lack certain chemicals in the blood.
(D)we lack oxygen in the blood