Consider the following statements with respect to angiosperms

Options

A. Male sex organ in a flower is the pistil
B. Anthers following mitosis produce pollen grains
C. In an embryo sac, the primary endosperm nucleus (PEN) is diploid
D. After double fertilization, ovules develop into seeds and ovaries into fruits.

Answer

To solve the question regarding the statements about angiosperms, we will analyze each statement one by one to determine their correctness.

### Step-by-Step Solution:

1. **Analyze Statement A**:
- The statement claims that the male sex organ in a flower is a pistil.
- **Correction**: The male sex organ in a flower is actually the stamen, not the pistil. The pistil is the female reproductive part of the flower.
- **Conclusion**: This statement is **incorrect**.

2. **Analyze Statement B**:
- The statement claims that the anther undergoes mitosis to produce pollen grains.
- **Correction**: The anther contains pollen mother cells, which undergo meiosis, not mitosis, to produce pollen grains.
- **Conclusion**: This statement is **incorrect**.

3. **Analyze Statement C**:
- The statement claims that the primary endosperm nucleus in an embryo sac is diploid.
- **Correction**: The primary endosperm nucleus is actually triploid (3n) in angiosperms, formed after fertilization when the polar nuclei fuse with a sperm cell.
- **Conclusion**: This statement is **incorrect**.

4. **Analyze Statement D**:
- The statement claims that after double fertilization, the ovule develops into the seed and the ovary develops into the fruit.
- **Correction**: This statement is true. In angiosperms, double fertilization occurs, leading to the formation of the seed from the ovule and the fruit from the ovary.
- **Conclusion**: This statement is **correct**.

### Final Conclusion:
- The only correct statement regarding angiosperms is **Statement D**. Therefore, the correct answer is **Option D**.