I changed my undershorts.  The elastic on the old ones I put on that day was deteriorated, and it completely failed when I dripped lab coffee on it, causing falldown.
 
        
                    
             
        
        
        
Answer:
Here are 5:
Distance from source to receiver
Wind speed and direction
Wind gradients
Temperature gradients
Atmospheric attenuation
and there are many more...
Hope that was helpful.Thank you!!!
 
        
             
        
        
        
C the third one i think good luck