H II regions are vast clouds of gas and dust in space, primarily composed of hydrogen that has been ionized by the intense ultraviolet radiation from nearby hot stars. These regions are often found in areas of active star formation, where new stars are born from the surrounding material. The ionization process causes the gas to glow, making H II regions visible in various wavelengths of light. These regions play a crucial role in the evolution of galaxies by contributing to the chemical enrichment of the interstellar medium. As stars within H II regions age and eventually explode as supernovae, they release heavy elements back into space, influencing the formation of new stars and planetary systems.