Question

question 6
when the mothers egg and the fathers sperm unite, each contributes
25,000 chromosomes.
one chromosome pair.
23 chromosomes.
23 chromosome pairs.

Explanation:

In humans, egg and sperm are gametes. Gametes are haploid cells. Human somatic cells have 46 chromosomes (23 pairs). Gametes (egg and sperm) are produced through meiosis. Meiosis reduces the chromosome number by half. So, each gamete (egg from mother and sperm from father) has 23 chromosomes. When they unite (fertilization), the zygote has 46 chromosomes (23 pairs).

• 25,000 is not the number of chromosomes in gametes. Human genome has about 20,000 - 25,000 genes.
• One chromosome pair: Gametes are haploid, they don't have pairs.
• 23 chromosome pairs: That's the number in somatic (non - gamete) cells.

Answer:

23 chromosomes.