All cellular activities that require energy use ATP as a source of energy. 
        
             
        
        
        
Answer:
C: Hormones
Explanation:
hormones do not "signal" other cells. I hope this helps :)
 
        
             
        
        
        
Answer:
The need for resources will make the organisms competitive in their ecosystems.
 
        
             
        
        
        
Answer:
The populations become adapted to different environments and eventually become so different that they cannot interbreed to produce fertile offspring.
Speciation is the evolution of one species into two different kinds, and when they become isolated, that is the final step, since they cannot interbreed any longer.
 
        
                    
             
        
        
        
Answer: D. They are not well adapted to the Australian climate.
Explanation:
Just took the exam