These preparations are called Vaccines. A vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing micro-organism and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins.
<span>C. less energy than X-rays and gamma rays.
Hope this helps!
</span>
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>
