Some factors could be:
weather
ressources
        
             
        
        
        
Answer:
yes they can
Explanation:
they go through the same chemical process/breakdown of food to create energy 
 
        
                    
             
        
        
        
Dichotomous Key with smiles
1. Teeth visible ....................go to 2
.....Teeth not visible .................go to 4
2. Has a wide, toothy smile .......Smilus toothyus
....Is not smiling ......................go to 3
3. Visibly crying .................Smilus dramaticus
.... Frowning .......................Smilus upsettus
4. Eyes are symmetrical .... go to 5
....Eyes not symmetrical .....go to 8
5. Eyes shaped like hearts ..... Smilus valentinus
....Eyes are shaped as ovals .....go to 6
<span>
</span>6. Smiling, happy face ...... Smilus traditionalis
.....Not happy, frowning or other .....go to 7
7. Mouth curved down, frowning .... Smilus saddus
.... Mouth is a small circle .................Smilus suprisus
8. Has a pirate eye patch ...............Smilus piratus
....Does not have eye patch ............ go to 9
9. One eye is much larger than the other eye ..... Smilus mutatus
One eye is winking .................Smilus winkus
 
        
             
        
        
        
City-state government was often conquered because they did not have enough resources to protect themselves
Explanation:
A city-state government is an independent autonomic political system which usually compromises just a single independent city which is governed by itself with sovereignty over its territory. The city-states like Greece, Italy, and Rome etc became very powerful. 
The main reason for these city-states being conquered more was the accumulation of wealth and aristocracy in such states.
Heavy taxes, religion, slavery also lead to social unrest and conflicts among these city-states which made them weaker.  These internal conflicts also made them lose their resources and vulnerable to be conquered by other powerful empires. 
With the increasing power of neighboring states, like in the case of Rome and Greece, the Romans became mightier than Greeks at one point and conquered the Greek city-states. 
 
        
             
        
        
        
Energy is the capacity of a physical system to perform work. Energy exists in several forms such as heat , kinetic or mechanical energy, light, potential energy , electrical, or other forms. Energy is the ability to do work. Energy sources could be classified as Renewable and Non-renewable.