Answer:
A chemical element is a type of atom with the same number of protons in their <u>atomic</u> nuclei. 
Explanation:
For an example, the atomic number of Chlorine is 17, and there is 17 protons in Chlorine.
If you have any questions feel free to ask in the comments.
 
        
                    
             
        
        
        
I believe the answer is Volcanic glass
        
             
        
        
        
B. is the correct answer I think 
        
             
        
        
        
Answer:
Groundwater depletion
Explanation:
Aquifer depletion is responsible for the collapse of land called Groundwater depletion