If 2n=12, the number of chromosomes in nucellus, integument and egg cell would be:

Options

A. 12, 12, 6
B. 12, 18 , 24
C. 12, 12 , 12
D. 12, 12, 24

Answer

To solve the question about the number of chromosomes in the nucellus, integument, and egg cell when 2n = 12, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- **Nucellus**: This is the central part of an ovule that contains the embryo sac. It is diploid (2n).
- **Integument**: This is the protective layer surrounding the ovule. It is also diploid (2n).
- **Egg Cell**: This is the female gamete, which is haploid (n).

2. **Identifying the Ploidy**:
- Since 2n = 12, we can deduce that:
- For diploid cells (nucellus and integument), the number of chromosomes is 12.
- For the haploid cell (egg cell), we need to find n, which is half of 2n.

3. **Calculating the Number of Chromosomes**:
- For the **Nucellus** (2n):
- Number of chromosomes = 12
- For the **Integument** (2n):
- Number of chromosomes = 12
- For the **Egg Cell** (n):
- Number of chromosomes = 2n / 2 = 12 / 2 = 6

4. **Final Answer**:
- Therefore, the number of chromosomes in:
- Nucellus = 12
- Integument = 12
- Egg Cell = 6

### Summary:
- Nucellus: 12 chromosomes
- Integument: 12 chromosomes
- Egg Cell: 6 chromosomes