Question

what meiotic event produces four gametes with abnormal numbers of chromosomes?
aneuploidy
unequal crossing over
meiosis ii nondisjunction
meiosis i nondisjunction
recombination

Explanation:

Meiosis I nondisjunction is the failure of homologous chromosomes to separate during meiosis I. This results in two daughter cells with an extra chromosome and two with a missing chromosome. All four subsequent gametes (after meiosis II) will have abnormal chromosome numbers. Aneuploidy is the result, not the event. Unequal crossing over and recombination affect genetic content, not chromosome number. Meiosis II nondisjunction only affects two gametes. Thus, meiosis I nondisjunction is the correct answer.

Answer:

meiosis I nondisjunction