13. what is the microtonal system? why is it so unusual to the ear trained in western music? what does it tell us about the universality of music intervals? could the human auditory system tolerate additional, intermediate piano keys inserted between the standard keys? 14. the structure of what type of song appears to be nearly universal in all cultures? 15. can human infants discriminate between consonant and dissonant sounds, or does this ability develop later in life? what are the roles of (i) the pre-wired brain architecture and (ii) the exposure of the fetus to sounds in the womb?