In humans, how many chromosomes are present in a mature egg cell (secondary oocyte) after meiosis has reduced the chromosome number?

• A. 92
• B. 23
• C. 22
• D. 46

Answer: (B)

Verified step by step guidance

1. Recall that human somatic cells are diploid (2n) with 46 chromosomes, meaning they have 23 pairs of chromosomes.
2. Understand that meiosis is the process that reduces the chromosome number by half to produce haploid (n) gametes, such as egg and sperm cells.
3. Recognize that a mature egg cell (secondary oocyte) is a haploid cell, so it contains only one set of chromosomes.
4. Therefore, after meiosis, the chromosome number in a mature egg cell is half of 46, which is 23 chromosomes.
5. This reduction ensures that when fertilization occurs, the resulting zygote has the correct diploid number of 46 chromosomes.