When we're doing scientific research, we should definitely be avoiding any sources which aren't scientific by nature. This means we should avoid sources which haven't been peer reviewed by fellow authors of a similar field. With this, we avoid using literature of questionable quality. 
        
             
        
        
        
Preserved footprints left behind by animals are called ichnites.
 
        
             
        
        
        
Answer:
C
Explanation:
Because between the earth and sun is empty space (vacuum) transfer of heat from the sun to earth can only occur through radiation-  because convection and conduction require a medium. The is the same process that warms your hands when you place them beside a fire. When you put your hands above the fire, they are warmed through convection.
 
        
             
        
        
        
It will help treat it, there's Hope of slowly treating it you have to have faith and patience.
Hope this helps :)
        
             
        
        
        
Answer:
Grain, species etc..
Explanation:
They were originally used to grind grain or spices or pump water and sawing wood. Now modern windmills are used for electricity.