Prophase -I of meiosis is a long and complex phase in which many events occurs . Arrange the following events of meiosis in the correct sequence and select correct option.
(i) Crossing over
(ii) Synapsis
(iii) Teminalization of chiasmata
(iv) Disappeance of nucleolus

Options

A. (i) ,(ii) ,(iii) ,(iv)
B. (ii) ,(iii) ,(iv) ,(v)
C. (ii) ,(i) ,(iv) ,(iii)
D. (ii) ,(i) ,(iii) ,(iv)

Answer

To solve the question regarding the correct sequence of events that occur during Prophase I of meiosis, we need to understand the specific phases and events that take place. Here’s a step-by-step breakdown of the events:

### Step-by-Step Solution:

1. **Understanding Prophase I**: Prophase I of meiosis is divided into several stages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis. Each of these stages has distinct events.

2. **Identifying the Events**:
- **Synapsis (ii)**: This is the process where homologous chromosomes pair up closely along their lengths. This occurs during the Zygotene stage.
- **Crossing Over (i)**: This event occurs during the Pachytene stage, where genetic material is exchanged between homologous chromosomes.
- **Terminalization of Chiasmata (iii)**: This occurs during the Diakinesis stage, where the points of crossing over (chiasmata) move to the ends of the chromosomes.
- **Disappearance of Nucleolus (iv)**: This event occurs at the end of Diakinesis, marking the transition to the next phase of meiosis.

3. **Arranging the Events in Sequence**:
- First, **Synapsis (ii)** occurs.
- Next, **Crossing Over (i)** takes place.
- Then, we have **Terminalization of Chiasmata (iii)**.
- Finally, the **Disappearance of Nucleolus (iv)** occurs.

4. **Final Sequence**: The correct order of events is:
- (ii) Synapsis
- (i) Crossing Over
- (iii) Terminalization of Chiasmata
- (iv) Disappearance of Nucleolus

### Correct Option:
Thus, the correct sequence is: **(ii) → (i) → (iii) → (iv)**.