I would choose the mountain ecosystem.
The mountain ecosystem contains a complex living organisms.
Mountain lands support a diverse array of habitats with large range of plants
and animals. It is very crucial for biological diversity and is very wonderful
to see. The climate is mostly cool which is fitting for relaxation.
 
        
                    
             
        
        
        
The correct answer to this question is this one: they lacked oxygen. The earliest organisms were completely heterotrophic in nature because of the reason that they lacked oxygen. <span>A heterotroph is an organism that cannot fix carbon and uses organic carbon for growth. </span>
        
             
        
        
        
It's B. The cheetah populations are less likely to be able to adapt to environmental changes.