When the pollen tube enters the embryo sac, which of the following cell usually gets burst on its entry:

Options

A. Both synergids
B. Central cell
C. Antipodals
D. One of the two synergids

Answer

To solve the question, "When the pollen tube enters the embryo sac, which of the following cell usually gets burst on its entry?", we will analyze the options provided and determine which cell is affected when the pollen tube penetrates the embryo sac.

### Step-by-Step Solution:

1. **Understanding the Embryo Sac Structure**:
- The embryo sac is a part of the ovule and contains several types of cells, including the egg cell, synergids, and the central cell.

2. **Identifying the Role of Synergids**:
- The synergids are located near the egg cell and play a crucial role in guiding the pollen tube to the egg for fertilization. They help in the reception of the pollen tube.

3. **Evaluating the Central Cell**:
- The central cell is involved in the formation of the endosperm after fertilization. It does not burst upon the entry of the pollen tube.

4. **Considering the Antipodal Cells**:
- Antipodal cells are located at the opposite end of the embryo sac and do not interact directly with the pollen tube. Therefore, they do not burst upon the entry of the pollen tube.

5. **Final Analysis of Synergids**:
- When the pollen tube enters the embryo sac, it typically penetrates through one of the synergids. Upon the entry of the pollen tube, the synergid cell usually bursts to allow the pollen tube to reach the egg cell.

6. **Conclusion**:
- Based on the analysis, the correct answer is that one of the two synergids bursts when the pollen tube enters the embryo sac.

### Final Answer:
**Option 4: One of the two synergids.**

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