The brain stem is the answer that you are looking for
        
                    
             
        
        
        
<span>Answer D hop you get it </span><span>Answer</span>
        
                    
             
        
        
        
Answer: Positive feedback loop
Explanation:
Even before the food reaches the stomach (before ingesting it), the glands of the stomach mucosa begin to release its gastric secretion. The main characteristic of this secretion is acidity, as measured by pH (one of the physiological variables). 
This acidity is a result of the presence of hydrochloric acid, which is part of the secretion composition. In addition to it, water, pepsinogen (which will give rise to the enzyme pepsin) and the intrinsic factor. The acid has a function of the protection of the entire system by eliminating microorganisms. It is also responsible for the activation of pepsin (which only occurs with acid pH), the enzyme that digests proteins containing the amino acids leucine or phenylalanine or tryptophan or tyrosine.
The concept of Positive feedback loop states that the body tries to increase the value of a variable (acidity, in the case of pepsinogen) when it is below its optimal value (called a point adjustment) and decreases this value when it is above optimal. 
 
        
             
        
        
        
The simple answer is, ALWAYS have an evacuation plan.
If in an earthquake stay away from cabinets, climb under a table or chair, and do the right sitting position (Hold on to your neck position.)
Hope I helped, would love if you left me a thanks! Thanks :)
        
                    
             
        
        
        
Answer:
Its main function is to act as a barrier to protect the body from the outside world. It also functions to retain body fluids, protect against disease, eliminate waste products, and regulate body temperature.
Explanation: