Question

which gamete results in trisomy if fertilized?
the one missing a chromosome
the one with no chromosomes
the one with four total chromosomes
the one with two copies of a chromosome

Explanation:

Trisomy is a chromosomal abnormality where there is an extra copy of a chromosome (three copies instead of the normal two). A gamete with two copies of a chromosome, when fertilized by a normal gamete (with one copy), will result in a zygote with three copies of that chromosome (trisomy). A gamete missing a chromosome leads to monosomy. A gamete with no chromosomes or four total chromosomes (without context of which chromosome is duplicated) is less likely to cause trisomy in the typical sense.

Answer:

the one with two copies of a chromosome