The answer is Neogene
Explanation:
It cannot be Cenozoic because that is an era. Not a period. Paleogene, Neogene, and Quaternary (our current period) are all periods within the Cenozoic Era (our current era). On the geologic time scale, there are Eras, Periods, and Epochs (and a few more classifications). Humans first appeared in the Miocene epoch which is an epoch in the Neogene period (in the Cenozoic era). 
This is why the answer is Neogene.
Hope this helps...
 
        
                    
             
        
        
        
Yes. It needs all its parts to survive.
        
                    
             
        
        
        
Why temperature affects heart rate in ectothermic organisms? If the temperature is within the optimal range for enzyme activity more ATP will be produced and the heart will beat faster due to increased metabolic activity and energy availability.