Question

these waves are used to send signals, including wifi and text messages. radio gamma microwaves ultraviolet

Explanation:

Radio waves are part of the electromagnetic spectrum. They have long wavelengths and low frequencies. In communication technology, radio waves are widely used. WiFi operates on specific radio - frequency bands (such as 2.4 GHz and 5 GHz). Text messages (SMS) are sent through cellular networks, and cellular communication also relies on radio waves for signal transmission. Gamma rays have very high energy and are not used for such common signal - sending purposes. Microwaves are used for cooking (in microwave ovens) and some short - range communication (but not as the primary means for general WiFi and text messages in the way radio waves are). Ultraviolet rays are mainly associated with things like sunburn, sterilization, and fluorescence, not with sending WiFi and text message signals.

Answer:

Radio