The features of modulation are : Modulation is the process of increasing the frequency of the signal to reduce the antenna height requirement. This is because the antenna height must equal to λ/4, for effective transmission. (Statement 3 is correct) Modulation enables Multiplexing of several message signal on a given channel, which is helpful in the transmission of different frequency signals through a single channel. (Statement 1 is correct) The Bandwidth requirement is increased when the message signal is modulated. This is primarily because the spectrum of the message signal is shifted by the presence of the carrier. (Statement 2 is not correct) No signal mixing so it provides better reception of message signal. It helps in transmitting message signals over long distances. (Statement 4 is correct)