In a cell with a diploid chromosome number of $2n = 12$, how many chromatids and chromosomes are present in each daughter cell at the end of Meiosis I?

Solution

1. The initial cell has $2n = 12$ chromosomes, meaning $12$ chromosomes and $24$ chromatids.
2. Meiosis I separates homologous chromosomes, reducing the chromosome count to $n=6$.
3. Each of these $6$ chromosomes remains in a replicated state consisting of $2$ sister chromatids.
4. Therefore, the daughter cells contain $6$ chromosomes and $12$ chromatids.
5. Hence the answer is (B).