Transduction of lower frequency sound waves occurs at the of the cochlea.
1. apex
2. base
3. middle
4. proximal end

The answer is the Apex of the cochlea

Explanation:

In the human ear, sound waves cause the stapes to press against the oval window. Vibrations travel up the fluid-filled interior of the cochlea. The basilar membrane that lines the cochlea gets continuously thinner toward the apex of the cochlea and different thicknesses of membrane vibrate in response to different frequencies of sound. Since the membrane in the cochlea is thinner towards the apex, sound waves frequency becomes lower.

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.