Norway rats have 42 chromosomes in their diploid cells. If such a cell enters meiosis, how many chromosomes and double-helical molecules of DNA will be present in each daughter cell at the end of meiosis II? a. 21 chromosomes and 21 double-helical DNA molecules b. 21 chromosomes and 42 double-helical DNA molecules c. 42 chromosomes and 42 double-helical DNA molecules d. 42 chromosomes and 84 double-helical DNA molecules

Verified step by step guidance

1. Understand that diploid cells (2n) have two sets of chromosomes. For Norway rats, the diploid number is 42, meaning there are 21 pairs of chromosomes.
2. Recognize that meiosis is a type of cell division that reduces the chromosome number by half, resulting in four haploid (n) cells. Each haploid cell will have half the number of chromosomes as the original diploid cell.
3. At the end of meiosis I, the cells are haploid, but each chromosome still consists of two sister chromatids. Thus, each cell has 21 chromosomes, each made of two chromatids, so there are 42 double-helical DNA molecules.
4. During meiosis II, the sister chromatids separate, and the cells divide again, but the number of chromosomes does not change. Each of the four resulting daughter cells ends up with 21 chromosomes.
5. Since the chromatids have separated, each chromosome now consists of a single double-helical DNA molecule. Therefore, each daughter cell has 21 chromosomes and 21 double-helical DNA molecules.