The Huns' invasion of Europe caused a mass migration driving Germanic tribes of Northern Europe to the borders of the Roman Empire which led to the Barbarian attacks on Rome. 
        
             
        
        
        
Answer: B. I hope you get this right.
 
        
             
        
        
        
The only force applied is gravity
        
             
        
        
        
Answer:
Radio waves are the lowest frequency
Explanation:
Here is the order of frequencies highest to lowest to help you in the future:
gamma rays
X-rays
ultraviolet radiation
visible light 
infrared radiation 
radio waves