<span>It helps scientists understand how populations and species react to changes in their environment, and this knowledge can be used to help these populations and species survive.</span>
        
             
        
        
        
Answer:
D) the sum of all physical properties of a substance
 
        
             
        
        
        
Answer:
My guess would be C
Explanation:
The crust, which is Earths outer solid layer of rock, is around 20km thick if I remembered correctly, and the ocean is nowhere near that, so there would be rock under the ocean.
If you find a better answer, then use it, because I'm not completely sure, but that's my best guess based on the possible answers