Spermatogonia is my answer
        
                    
             
        
        
        
Answer: C. building cars that can better withstand collisions
 
        
             
        
        
        
Answer:
Explanation: In facilitated diffusion, molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers. A concentration gradient exists for these molecules, so they have the potential to diffuse into or out of, the cell by moving down it.
 
        
             
        
        
        
Answer:
Climatology 
Explanation: Climatology is the study of climate and how it changes over time. This helps people have a better understanding of the atmospheric conditions which can cause weather patterns and temperature changes over time.