Answer is: <span>nondisjunction.
</span>Nondisjunction<span> is the failure of </span>homologous chromosomes<span> to separate correctly during </span>cell division, because of tha daughter cells have abnormal chromosome numbers. This example is <span>failure of a pair of </span>homologous chromosomes<span> to separate in </span><span>meiosis I.</span>
The eardrum is a thin flap of skin that is stretched tight like a drum and vibrates when sound hits it.
The structure is calcium ions.