In angiosperms, central cell of embryo sac, prior to entry of pollen tube contains

Options

A. Two haploid polar nuclei
B. One diploid secondary nucleus
C. A single haploid nucleus
D. One diploid and one haploid nucleus

Explanation

To answer the question regarding what the central cell of the embryo sac in angiosperms contains prior to the entry of the pollen tube, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Structure**: In angiosperms, the embryo sac is a crucial part of the ovule. It contains several cells, including the central cell, which plays a significant role in fertilization.

2. **Identifying the Central Cell**: The central cell of the embryo sac is located at the center of the sac and is important for the fertilization process.

3. **Nuclear Composition Before Fertilization**: Before the entry of the pollen tube, the central cell contains two haploid nuclei known as polar nuclei. These nuclei are crucial for the fertilization process.

4. **Fertilization Process**: When the pollen tube enters the embryo sac, one of the sperm cells fertilizes the egg cell, while the other sperm cell fuses with the two haploid polar nuclei in the central cell. This fusion results in the formation of a diploid secondary nucleus.

5. **Conclusion**: Therefore, prior to the entry of the pollen tube, the central cell of the embryo sac contains two haploid polar nuclei.

### Final Answer:
The correct option is **a. two haploid polar nuclei**.

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