Chromosome number is reduced during meiosis because the process consists of-

Options

A. Two cell divisions without any chromosome replication
B. A single cell division without.any chromosome replication
C. Two cell division in which half of the chromosomes are destroyed
D. Two cell divisions and only single round of chromosome replication

Answer

To understand why the chromosome number is reduced during meiosis, we need to break down the process step by step:

### Step-by-Step Solution:

1. **Understanding Meiosis**: Meiosis is a specialized type of cell division that reduces the chromosome number by half. It consists of two main stages: Meiosis I and Meiosis II.

2. **Phases of the Cell Cycle**: Before meiosis begins, the cell goes through the interphase, which includes G1 (Gap 1), S (Synthesis), and G2 (Gap 2) phases. During the S phase, DNA replication occurs, resulting in duplicated chromosomes.

3. **Meiosis I**: In Meiosis I, homologous chromosomes are separated. This is the first division, and it reduces the chromosome number from diploid (2n) to haploid (n). Each daughter cell receives one chromosome from each homologous pair.

4. **Meiosis II**: In Meiosis II, the sister chromatids of each chromosome are separated. This division is similar to mitosis, but since the cells are already haploid, the chromosome number remains the same in each of the two divisions.

5. **Result of Meiosis**: At the end of meiosis, from one diploid cell, four haploid cells are produced. This reduction in chromosome number occurs because there is one round of DNA replication (during S phase) followed by two rounds of cell division (Meiosis I and Meiosis II).

6. **Conclusion**: Therefore, the chromosome number is reduced during meiosis because it involves one round of DNA replication followed by two rounds of cell division.

### Final Answer:
The chromosome number is reduced during meiosis because the process consists of one round of DNA replication (S phase) and two rounds of cell division (Meiosis I and Meiosis II).