This is cyclic change because the population is consistently going up and back down.
 
        
             
        
        
        
Is this a question? True or false?
        
                    
             
        
        
        
<h3><u>Answer;</u></h3>
A. Gas exchanges takes place by diffusion. 
B. It is an open system.
<h3><u>Explanation</u>;</h3>
- Most molluscs and arthropods have an open type of circulatory system. 
- Open circulatory systems pump blood into a hemocoel with the blood diffusing back to the circulatory system between cells. 
- Blood is pumped by a heart into the body cavities, where tissues are surrounded by the blood. 
 
        
        
        
Answer:
Cellular respiration :)
Explanation:
Your body cells use the oxygen you breathe to get energy from the food you eat.  During cellular respiration the cell uses oxygen to break down sugar. Breaking down sugar produces the energy your body needs
 
        
             
        
        
        
Answer:It produces antigens which stimulate a fever.
Explanation: