To smell and feel surfaces and sense temperatures
        
             
        
        
        
The esophagus has a simple but significant functions to animals who has it. These functions can be a) to swallow food and serve as a passageway to the stomach and b) may serve to release the eaten food that might have some harmful compositions or chemicals -the vomit response. 
        
             
        
        
        
Protein-energy malnutrition is a form of undernutrition caused by an extremely deficient intake of calories, protein, or both. Two examples of this type of malnutrition are kwashiokor and marasmus. Protein-energy malnutrition is more often caused by decreased absorption or abnormal metabolism. It  is defined as a range of pathological conditions arising from coincident lack of protein and/or energy in varying proportions. The condition vary in forms ranging from mild through moderate to severe degrees.