Ploidy level of Nucellus, endosperm, polar nuclei , Megaspore mother cell, female gametophyte respectively are:

Options

A. 2n, 3n, n, 2n, n
B. 2n,3n,2n,n,n
C. n, 2n, n, 2n, n
D. 2n,3n,2n,2n,n

Answer

To solve the question regarding the ploidy levels of the nucellus, endosperm, polar nuclei, megaspore mother cell, and female gametophyte, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Nucellus:**
- The nucellus is a part of the ovule and serves as a nutritive tissue for the developing embryo. Since it is part of the ovule, which is derived from the sporophyte generation, the ploidy level of the nucellus is diploid (2N).

2. **Determine the Ploidy of Endosperm:**
- The endosperm is formed after fertilization when the second male gamete fuses with the two polar nuclei. This results in a triploid (3N) structure because it contains three sets of chromosomes (one from the male gamete and two from the polar nuclei).

3. **Analyze the Polar Nuclei:**
- The polar nuclei are part of the female gametophyte (embryo sac) and are haploid (N). Since there are two polar nuclei, each is N, but together they contribute to the formation of the triploid endosperm.

4. **Examine the Megaspore Mother Cell:**
- The megaspore mother cell, which undergoes meiosis to produce megaspores, is also part of the ovule and is therefore diploid (2N).

5. **Identify the Female Gametophyte:**
- The female gametophyte, represented by the embryo sac, is derived from the megaspores and is haploid (N).

### Summary of Ploidy Levels:
- Nucellus: 2N (Diploid)
- Endosperm: 3N (Triploid)
- Polar Nuclei: N (Haploid)
- Megaspore Mother Cell: 2N (Diploid)
- Female Gametophyte: N (Haploid)

### Final Answer:
The ploidy levels of the respective structures are:
- Nucellus: 2N
- Endosperm: 3N
- Polar Nuclei: N
- Megaspore Mother Cell: 2N
- Female Gametophyte: N