Energy is always lost as energy is moved from one level to another. ... The loss of energy due to the second law of thermodynamics results in a pyramid with a large base and a 10% ratio between levels.
 
        
             
        
        
        
It is called  a population since they are all the same species 
        
                    
             
        
        
        
Answer:
Mammals undoubtedly play an important role in ecosystems by providing essential services such as seed dispersal, pollination and regulating insect populations, and reducing disease transmission [20–22] and there is some evidence that some groups act as indicators of general ecosystem health [23].
Explanation:
 
        
             
        
        
        
The answer's B. hypothalamus
mark me brainliesttt :)))