Why does SETI examine radio waves?

SETI (Search for Extraterrestrial Intelligence) examines radio waves because they are a promising medium for interstellar communication due to their ability to travel vast distances without significant distortion. Radio waves can penetrate cosmic dust and gas, making them an effective way to detect signals from distant civilizations. Additionally, the frequency ranges chosen by SETI are often less likely to be obscured by natural astrophysical phenomena, increasing the chances of detecting intentional signals from intelligent sources.