Final answer:
The statement that high frequencies are best heard at the base of the cochlea is true; as the cochlea and the basilar membrane within it differentiate sound frequencies, with the base responding to high frequencies.
Step-by-step explanation:
The statement that high frequencies are best heard at the base of the cochlea (basilar membrane) is true. According to the place theory of pitch perception, the cochlea acts in a way similar to a prism, separating sounds into their component frequencies. The base of the basilar membrane, which is at the entrance near the oval window, is responsive to high-frequency sounds, and these sounds do not travel far along the membrane before causing it to vibrate. On the other hand, lower frequencies have their maximal effect further along the basilar membrane, towards the apex or tip of the cochlea. Hair cells located along the cochlear duct have tuned frequencies, with those at the base being most sensitive to higher frequencies (>20 kHz) and those at the apex responding to lower frequencies (~20 Hz).