What is the correct ploidy sequence in the following ?
(A) Protonema cell of moss
(B) Capsule cell of liverworts
(C) Roots cell of Pteridophyta
(D) Gymnospermic endosperm

Options

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

Answer

To determine the correct ploidy sequence for the given options, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Protonema Cell of Moss**:
- The protonema is a stage in the life cycle of mosses that develops from the germination of spores.
- Mosses are gametophytes, and the protonema is haploid.
- **Ploidy**: N (haploid)

2. **Capsule Cell of Liverworts**:
- The capsule of liverworts is part of the sporophyte generation, which is diploid.
- The cells in the capsule are derived from the zygote and are therefore diploid.
- **Ploidy**: 2N (diploid)

3. **Root Cell of Pteridophyta**:
- Pteridophytes (ferns and their relatives) have a dominant sporophyte generation.
- The root cells are part of the sporophyte and are diploid.
- **Ploidy**: 2N (diploid)

4. **Gymnospermic Endosperm**:
- In gymnosperms, the endosperm is formed from the fertilization of the egg cell and is typically haploid.
- Unlike angiosperms, gymnosperms do not undergo double fertilization, so the endosperm remains haploid.
- **Ploidy**: N (haploid)

### Summary of Ploidy Sequence:
- (A) Protonema cell of moss: N
- (B) Capsule cell of liverworts: 2N
- (C) Roots cell of Pteridophyta: 2N
- (D) Gymnospermic endosperm: N

### Correct Ploidy Sequence:
The correct ploidy sequence is: N, 2N, 2N, N.

### Final Answer:
The correct answer is option **(2)**, which corresponds to the sequence: N (Protonema cell of moss), 2N (Capsule cell of liverworts), 2N (Roots cell of Pteridophyta), N (Gymnospermic endosperm).