The embryo sac of an angiosperm is made up of :

Options

A. 8 cells
B. 7 cells and 8 nuclei
C. 8 nuclei
D. 7 cells and 7 nuclei

Explanation

To solve the question regarding the composition of the embryo sac in angiosperms, we will follow these steps:

### Step-by-Step Solution:

1. **Understanding the Ovule Structure**:
- The ovule in angiosperms represents the megasporangium and is located within the ovary of the flower. The ovule contains the embryo sac, which is the female gametophyte.

2. **Megasporogenesis Process**:
- Megasporogenesis is the process by which the megaspores are formed from the megaspore mother cell through meiosis.
- A single megaspore mother cell undergoes meiosis to produce four haploid megaspores (tetrad).

3. **Monosporic Development**:
- In angiosperms, typically, only one of these four megaspores remains functional (the others degenerate), leading to monosporic development.

4. **Nuclear Division**:
- The functional megaspore undergoes mitotic divisions. Initially, it divides to form two nuclei, which then migrate to opposite poles of the cell.
- Further mitotic divisions occur, resulting in a total of eight nuclei within the embryo sac.

5. **Cellularization**:
- After reaching the eight-nucleated stage, cell walls begin to form around the nuclei.
- This results in the formation of seven cells:
- Three antipodal cells at one end,
- Two synergids and one egg cell at the other end,
- The central cell contains two polar nuclei.

6. **Final Count**:
- Thus, the embryo sac is characterized by having **7 cells** and **8 nuclei**.

### Conclusion:
The correct answer to the question is that the embryo sac of an angiosperm is made up of **7 cells and 8 nuclei**.