As clearly explained throughout Śrīmad-Bhāgavatam, the first element, sky, possesses the unique quality of sound. As creation expands, the second element, air, comes into being, and it possesses sound and touch. The third element, fire, possesses sound, touch and form, and the fourth element, water, possesses sound, touch, form and flavor. The earth possesses sound, touch, form, flavor and aroma. As each element loses its unique distinguishing quality, it naturally becomes indistinguishable from the more subtle elements and is thus effectively dissolved as a unique entity.