Answer:
X: Positive gravitropism
Y: Negative gravitropism
Explanation:
i just did the quiz and got it correct 
 
        
                    
             
        
        
        
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.