AP Biology question on Meiosis? THANKS! D?

One common genetic disorder is Down Syndrome. In this phenotype, the individual has an extra chromosome 21, called trisomy-21. Meiosis is the splitting of genetic materials in cells that results in two haploids (or gametes). One way trisomy-21 can occur is through nondisjunction, when chromosomes fail to seperate during meiosis and could result in an extra chromosome after the two haploids bind together. Try looking at some of the videos at a href="http://www.teachersdomain.org/resource/tdc02.sci.life.gen.lp_disorder/" rel="nofollow"http://www.teachersdomain.org/resource/t…/a for a better understanding.