Four different steps that occur during meiosis are given in the following list.
(i) Complete separation of chromatids
(ii) Pairing of homologous chromosomes
(iii) Lining up of paired chromosomes on equator
(iv) Crossing over between chromatids
Select the correct sequential arrangement of the steps.

Options

A. ii,iii,iv,i
B. iii,ii,iv,i
C. ii,iv,iii,i
D. iii,i,ii,iv

Explanation

To determine the correct sequential arrangement of the steps that occur during meiosis, we need to analyze the provided steps and their respective stages in the meiotic process.

### Step-by-Step Solution:

1. **Identify the Steps**:
- (i) Complete separation of chromatids
- (ii) Pairing of homologous chromosomes
- (iii) Lining up of paired chromosomes on equator
- (iv) Crossing over between chromatids

2. **Determine the Stages of Meiosis**:
- **Meiosis I** consists of several stages:
- **Prophase I**: This includes several sub-stages:
- **Zygotene**: Pairing of homologous chromosomes occurs here (Step ii).
- **Pachytene**: Crossing over occurs here (Step iv).
- **Metaphase I**: Lining up of paired chromosomes on the equator occurs here (Step iii).
- **Anaphase I**: Complete separation of chromatids occurs here (Step i).

3. **Sequence the Steps**:
- From the analysis:
- Step (ii) - Pairing of homologous chromosomes occurs first during Zygotene.
- Step (iv) - Crossing over occurs next during Pachytene.
- Step (iii) - Lining up of paired chromosomes occurs during Metaphase I.
- Step (i) - Complete separation of chromatids occurs last during Anaphase I.

4. **Final Arrangement**:
- The correct sequential arrangement of the steps is:
- (ii) Pairing of homologous chromosomes → (iv) Crossing over between chromatids → (iii) Lining up of paired chromosomes on equator → (i) Complete separation of chromatids.
- Therefore, the correct sequence is **2, 4, 3, 1**.

### Conclusion:
The correct sequential arrangement of the steps during meiosis is **2, 4, 3, 1**.

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