Question

which of these can result in a trisomy such as down syndrome?
○ an egg with 23 chromosomes fertilized by a sperm with 23 chromosomes
○ an egg with 23 chromosomes fertilized by a sperm with 22 chromosomes
○ an egg with 22 chromosomes fertilized by a sperm with 24 chromosomes
○ an egg with 22 chromosomes fertilized by a sperm with 23 chromosomes
○ an egg with 24 chromosomes fertilized by a sperm with 23 chromosomes

Explanation:

Trisomy occurs when there is an extra chromosome in a cell. Normal human cells have 46 chromosomes (23 pairs). In the case of fertilization, if an egg or sperm has an abnormal number of chromosomes, it can lead to trisomy. An egg with 24 chromosomes (one extra) fertilized by a normal sperm with 23 chromosomes will result in a zygote with 47 chromosomes (trisomy).

Answer:

an egg with 24 chromosomes fertilized by a sperm with 23 chromosomes