High intensity sounds are perceived as relatively loud sounds. The sound waves which are most intense and perceived as loud sounds are those which have a . Identify the one characteristic which is unique of such sound waves.

Explanation:

loud sound depends on amplitude, intensity, frequency and energy.

as already mention high intensity sounds are perceived as loud sounds.

and the intensity of the sound is the rate at which the energy through a cross sectional area of a medium. higher intensity means higher amplitude. if we put more energy as source means we providing higher amplitude vibrations to the particles which cause the increase in intensity result is louder sound.

it is very well related to a lot of things but with my limited knowledge i can confidently say that the answer is space.