Extensive properties, as volume and mass, depend on the amount of material. So, you can have a sample of gold and a sample of copper with the same volume as long as you have different amount of each one.
On the other hand, intensive properties do not depend on the amound of material but on the chemical constitution of the material. Density is an intensive property, so gold and copper have different densities. That is why you can use intensive properties to characterize different materials.
        
             
        
        
        
Answer:
A. Warning
Explanation:
Out of all said choices, the best choice would be warning since it would fit the sentence the most. 
"A Warning notifies you that danger is present." compared to: 
"A Hazard notifies you that danger is present."
"A Safety notifies you that danger is present."
"A Danger notifies you that danger is present."
 
        
             
        
        
        
Answer:
the sun
Explanation:
the sun is not alive and plants use photosynthesis to eat the radiation emitted by the sun.
 
        
             
        
        
        
Answer:
             CH3
             |
CH3-    C H  -CH2-CH2-      CH   - CH2-CH2-CH3
                                               |
                                               CH
                                            /     \
                                          CH3  CH3
Explanation:
Octan 
C-C-C-C-C-C-C-C
Metyl 
CH3 -
Isopropyl
      CH3
     / 
- CH
    \
      CH3
2-metil-5-isopropiloctan
            CH3
             |
CH3-    C H  -CH2-CH2-      CH   - CH2-CH2-CH3
                                               |
                                               CH
                                            /     \
                                          CH3  CH3