During normal meiosis, homologous chromosomes pair up and separate so that each gamete receives a copy of every chromosome. sometimes an error is made during this separation and homologous chromosomes fail to separate. this results in one gamete that has two copies of the chromosome, and another gamete that does not have the chromosome at all. this type of error is known as and usually results in zygotes that either do not develop to term or have severe abnormalities. a. chromosome inversion b. chromosome insertion c. chromosome translocation d. chromosome nondisjunction