In humans, the first polar body formed during oogenesis has
(i) 46 chromosomes
(ii) 23 chromosomes
(iii) 46 chromatids
(iv). 23 chromatids

Options

A. (ii) and (iv)
B. (ii) and (iii)
C. (i) and (iii)
D. (i) and (iv)

Answer

To solve the question regarding the number of chromosomes and chromatids in the first polar body formed during oogenesis in humans, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Oogenesis**:
- Oogenesis is the process of egg (ovum) formation in females. It begins with a diploid cell called the oogonium, which undergoes mitosis to form a primary oocyte.

**Hint**: Remember that oogenesis starts with a diploid cell, which means it has two sets of chromosomes.

2. **Meiosis in Oogenesis**:
- The primary oocyte undergoes the first meiotic division (meiosis I), which is a reduction division. This division results in two cells: one secondary oocyte and one polar body.

**Hint**: Meiosis reduces the chromosome number by half, so keep track of how many chromosomes are in each cell after division.

3. **Chromosome Count**:
- In humans, the diploid number (2n) of chromosomes is 46. After meiosis I, the secondary oocyte and the polar body each receive half of the chromosomes, which is 23 chromosomes (n).

**Hint**: The polar body is a byproduct of oogenesis and typically does not contribute to fertilization.

4. **Chromatid Count**:
- Each chromosome consists of two chromatids at this stage (before the second meiotic division). Therefore, if the polar body has 23 chromosomes, it will have 23 x 2 = 46 chromatids.

**Hint**: Remember that chromatids are the two identical halves of a duplicated chromosome.

5. **Conclusion**:
- The first polar body formed during oogenesis has 23 chromosomes and 46 chromatids. Therefore, the correct answer to the question is:
- (ii) 23 chromosomes
- (iv) 46 chromatids

### Final Answer:
The first polar body formed during oogenesis in humans has **(ii) 23 chromosomes** and **(iv) 46 chromatids**.

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