Which of the following is the disadvantage of $FM$ over $AM$?

Given below are two statements
Statement $I:$ For transmitting a signal,the size of the antenna $(l)$ should be comparable to the wavelength of the signal (at least $l = \frac{\lambda}{4}$ in dimension).
Statement $II:$ In amplitude modulation,the amplitude of the carrier wave remains constant (unchanged).
In the light of the above statements,choose the most appropriate answer from the options given below.

For sky wave propagation of a $10\, MHz$ signal, what should be the minimum electron density in the ionosphere?

In a frequency modulated wave:

Modulation is a process of superposing

The maximum distance up to which $TV$ transmission from a $TV$ tower of height $h$ can be received is proportional to