Answer:
common meaning of tree is :
supply of oxygen
 
        
             
        
        
        
A. This is because these formations occur on the surface and can range from mountains to forests.
        
                    
             
        
        
        
C, because it is bounded to the west by the Black Sea
        
             
        
        
        
Everybody always uses it to mean some kind of liquid that's hot and smoking, 
like glowing smoking molten lava creeping down the sides of a volcano, or red 
hot molten steel pouring out of the furnace in a steel mill in a shower of sparks.  
But I think technically it just means melted ... water is molten ice.
        
                    
             
        
        
        
It begins at the Baikal Mountains in Russia and ends at the Lena Delta into the Arctic ocean, also found in Russia.