Question

downs syndrome occurs because of non - disjunction. as a result, individuals with downs syndrome

Explanation:

Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21. Non - disjunction during meiosis (the process of cell division to form gametes) results in a gamete (sperm or egg) having an extra chromosome 21. When this gamete fuses with a normal gamete during fertilization, the resulting zygote has three copies of chromosome 21 instead of the normal two.

Answer:

additional 21st chromosome