Given below are the steps involved in oogenesis . Arrange them in proper sequence and select the correct option.
1. Formation of primary follicle due to development of granulosa cells.
2 Division of oogonia and formation of the primary oocyte.
3. Formation of follicles having antrum .
4. Formation of secondary follicles.
5. An unequal division leading to the formation of secondary oocyte i.e. ovum and the first polar body .

Options

A. 1, 3 ,4 ,2 ,5
B. 2 ,1 ,4, 3, 5
C. 3, 1 ,2 ,4, 5
D. 1, 5, 3, 2 ,4

Answer

To arrange the steps involved in oogenesis in the correct sequence, we need to understand the process clearly. Here’s a step-by-step breakdown:

### Step-by-Step Solution:

1. **Division of Oogonia and Formation of the Primary Oocyte (Step 2)**:
- Oogonia, which are the precursor cells, undergo mitotic division to form primary oocytes. This is the initial step in oogenesis.

2. **Formation of Primary Follicle due to Development of Granulosa Cells (Step 1)**:
- Once primary oocytes are formed, they get surrounded by a layer of granulosa cells, leading to the formation of primary follicles.

3. **Formation of Secondary Follicles (Step 4)**:
- The primary follicles develop further, adding more layers of granulosa cells and forming secondary follicles.

4. **Formation of Follicles Having Antrum (Step 3)**:
- The secondary follicles develop a fluid-filled cavity called the antrum, transforming into tertiary follicles.

5. **An Unequal Division Leading to the Formation of Secondary Oocyte and the First Polar Body (Step 5)**:
- Finally, the primary oocyte within the tertiary follicle completes its first meiotic division, resulting in an unequal division that produces a secondary oocyte (the ovum) and a smaller first polar body.

### Correct Sequence:
The correct sequence of the steps involved in oogenesis is:
2 → 1 → 4 → 3 → 5

### Answer:
The correct option is the one that reflects this sequence, which is the second option.