I THINK its (A) im sorry if im wrong i tried reading about it 
 
        
                    
             
        
        
        
<span>pollution, mineral location, and new energy sources
space exploration and national defense
microbiology advancements and cloning procedures
</span>
        
             
        
        
        
are you gonna give me the user and pass
 
        
                    
             
        
        
        
Answer: Prophase
Do check if the answer’s correct, it’s been long since I’ve looked into the stages.
        
             
        
        
        
The correct answer is: Heartburn often results when the gastroesophageal sphincter fails to close properly.
The gastroesophageal sphincter is a muscle located at the bottom of the esophagus that has to be relaxed in order to allow food to flow down into the stomach. After it contracts (tightens), the food and the stomach acid can’t flow back up into the esophagus.
When the gastroesophageal sphincter fails to close properly acid reflux occurs and causes the heartburn.