In an embryo sac, the cells that degenerate after fertilisation are

Options

A. synergids and primary endosperm cell
B. synergids and antipodals
C. antipodals and primary endosperm cell
D. egg and antipodals.

Answer

To answer the question, "In an embryo sac, the cells that degenerate after fertilization are," we need to understand the structure of the embryo sac and the process of fertilization in flowering plants (angiosperms).

### Step-by-Step Solution:

1. **Understanding the Embryo Sac Structure**:
- The embryo sac is a female gametophyte that contains several cells, including the egg cell, synergids, polar nuclei, and antipodal cells.

2. **Identifying the Process of Fertilization**:
- In angiosperms, fertilization involves a process known as double fertilization. This includes:
- **Syngamy**: The fusion of the egg cell (female gamete) with one of the male gametes to form the zygote.
- **Triple Fusion**: The fusion of the two polar nuclei in the central cell with the second male gamete to form the primary endosperm nucleus.

3. **Determining Which Cells Degenerate**:
- After fertilization, not all cells in the embryo sac are needed. The following cells degenerate:
- **Synergids**: These cells help guide the pollen tube to the egg cell, but they are not needed after fertilization.
- **Antipodal Cells**: These cells are located at the opposite end of the embryo sac and do not play a role in the development of the embryo or endosperm after fertilization.

4. **Conclusion**:
- The cells that degenerate after fertilization are the **synergids and the antipodal cells**.

### Final Answer:
The cells that degenerate after fertilization in an embryo sac are the **synergids and the antipodals**.