<em>Sound from the external environment is collected by the outer ear.</em> It then passes through <em>the auditory canal and reaches the tympanum. </em>
The <em>tympanum then vibrates</em> and these vibrations are then sent to the middle ear which consists of three small bones called malleus, incus and stapes. The sound is amplified by these<em> tiny bones and the amplified sound is sent to the inner ear.
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From the inner ear the sound signals are converted into electrical signals and the auditory nerve sends these signals to the brain. <em>What takes place here is transduction .
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Metaphase is the stage in which the "crossing over" occurs.
As we know chromosomes carry genetic information. This crossing over process happens in eukaryotic cells and occurs during the mitosis phases of cell division.