Which have scientists learned from studying seismic waves that travel through earth’s interior?

A.
Earth's mantle is liquid.

B.
Seismic waves are not affected by boundaries between earth's layers.

C.
Seismic waves cannot move through solid objects.

D.
The outer core of earth is liquid.
PLEASE ANSWER MY QUESTION FOR A METAL PLAESE AND THANK YOU

Question

Which have scientists learned from studying seismic waves that travel through earth’s interior?  
 
 

 
 

  

  A. 
  Earth's mantle is liquid.   
   

 
 

  

  B. 
  Seismic waves are not affected by boundaries between earth's layers.   
   

 
 

  

  C. 
  Seismic waves cannot move through solid objects.   
   

 
 

  

  D. 
  The outer core of earth is liquid.  
PLEASE ANSWER MY QUESTION FOR A METAL PLAESE AND THANK YOU