Because hormones secreted by endocrine glands regulate the activity of body cells ..the release of body hormones into the blood is controlled by a stimulus either causes an increase or a decrease in the amount of hormone secreted .
        
             
        
        
        
Answer:
because they can donate blood to anyone
Explanation:
 
        
                    
             
        
        
        
The answer is fundamental niche
        
             
        
        
        
Because acids have a bitter taste i believe