The correct answer is a structure that would differentiate the hollow heart into chambers to separate oxygenated blood. 
The heart has four chambers: two ventricles and two atria. The right atrium gets oxygen-poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the oxygen-deficient blood to the lungs.
The left atrium gets oxygen-enriched blood from the lungs and pumps it to the left ventricle, and the left ventricle pumps the oxygen-enriched blood to the body. The right and left atrium are distinguished by a wall of tissue known as the atrial septum, and the left and right ventricles are separated by the ventricular septum.
 
        
                    
             
        
        
        
Carbohydrates are not important as a stimulus in the gastric phase of gastric secretion, whereas distension, peptides, and low acidity are.
        
             
        
        
        
I would guess rainforest because it’s an reptile/amphibian it appears and those animals need water to survive. There isn’t much water in the dessert.
        
             
        
        
        
D. the 4 types of tissues in the body are: muscle, nerve, connective and epithelial