Cochlea a protein motor called prestin on their outer membranes; it generates additional movement that couples back to the fluid–membrane wave. This "active amplifier" is essential in the ear's ability to amplify weak sounds. The active amplifier also leads to the phenomenon of soundwave vibrations being emitted from the cochlea back into the ear canal through the middle ear (otoacoustic emissions). Otoacoustic emissions are due to a wave exiting the cochlea via the oval window, and propagating back through the middle ear to the eardrum, and out the ear canal, where it can be picked up by a microphone. Otoacoustic emissions
Stirrup jar been made, but are generally unsupported. The most common, wine, had its own battery of containers from serving and drinking ware (cups, mixers, bowls, etc.) to transport vessels, the amphorae, which are generally larger and more plentiful than stirrup-jars. Wine was apparently more plentiful. Oil requires a significant investment in olive trees, which cannot be harvested for several years after planting. A third suggestion, perfume, is not compatible with the small quantities placed in perfume jars, which are always very small. The relatively large stirrup jars would represent unrealistically huge amounts of perfume. The early stirrup-jars were not distinguished by