Answer:
Exercise causes the heart to pump blood into the circulation more efficiently as a result of more forceful and efficient myocardial contractions, increased perfusion of tissues and organs with blood, and increased oxygen delivery.
Explanation:
 
        
             
        
        
        
Answer:
A tan might indicate sun damage to the skin.
Explanation:
Tanning is the process by which the skin is exposed to the ultraviolet rays that comes from the sun with the purpose of producing a dark-brown coloration called a TAN. 
A tan achieved by exposure to the sun can actually indicate that a person's skin is undergoing damage from the UV rays of the sun, hence, the skin responds by producing a protein called melanin, which protects the skin and later forms the dark coloration- tan. From this explanation, tan is got in response to a damaging signal received by the cell, hence, a tan might indicate sun damage to the skin.
 
        
             
        
        
        
Answer:
A frog and humans 
Explanation:
A frog develops and changes during its lifecycle,also a human thy grow as they age.
 
        
                    
             
        
        
        
There are far to many variables to make a true accurate answer, this is coming from a medical responder BUT lots of texts say about 120 min....but that's very much debatable