The answer to this question is :
D. Obstacle Evaluation
        
                    
             
        
        
        
<span>First, chemical energy from organic molecules is used to make ATP (Adenosine triphosphate) in cellular respiration, after which ATP provides energy for biological processes.</span>
        
                    
             
        
        
        
Answer:
The answer is A. a natural disaster killed off the population by flooding their habitat. 
Explanation:
I had to do the assignment.