D. Density 
The bulk density of a planet will reflect the relative amounts of the materials the world is made of, regardless of what materials occur at the surface. 
 
        
                    
             
        
        
        
It is wet because it is touching the water. it is a natural habitat, so the fish itself does not feel wet.
        
                    
             
        
        
        
Answer:
The correct answer is: A) Asteroid belt.
Explanation:
All of the other events can be explained by colliding worlds in the early solar system but the asteroid belt can't. The asteroid belt originated from the primitive solar nebula as a congregation of planetesimals, which were the precursors of the protoplanets.