Answer:
I believe it's ecological succession. 
Hope that helps!
 
        
                    
             
        
        
        
Because their bodies tell them that they need more oxygen and so breathe faster, and try and get the oxygen their body requires and depends on.
        
             
        
        
        
Answer:
Primitive Earth where life emerged was subjected to extreme conditions  
Explanation:
The origin of life is still an issue of intense debate today, although most researchers believe that life emerged from primitive organisms generated by the synthesis of organic compounds in early Earth. In line with this theory, it has been shown that membrane-forming compounds can be formed in extreme conditions (i.e., UV rays, extreme temperature, etc). It is believed that such conditions recreated in a laboratory were similar to the early Earth about 3,900 million years ago, thereby supporting the idea of the 'primordial soup theory' proposed by John Burdon Sanderson Haldane in 1929.
 
        
             
        
        
        
Answer: Cellulose 
Explanation:
Starch and cellulose are they two primary polysacharride found in plants.
Starch is the storage polysacharride found in plants in consisting of both linear chain amylose and branch chain amylopectin.
While Cellulose is the structural polysacharride in cell wall of plants. Cellulose consist of a linear chain of thousands of D-glucose units linked together by beta linkages.
 
        
             
        
        
        
What's the question here?