What properties of radio waves makes them suitable for sending signals in mountainous regions?

one of the property of radio waves is that they have long wavelength. due to their long wavelength , they undergo diffraction around the mountains and thus the waves spread around the mountain. this makes them eligible to be used for  long distance communication. they can coded and decoded also . that is why they are used in television and radio system

c. magnitude and direction

can u provide the graph and if its not possible

then i can tell u the segment where the

average time interval starts degrading is the segment where the car is slowing down