The significance of double fertilization is that it

Options

A. provides stimulus to resume growth of embryo sac
B. ensures the formation of endosperm only after fertilization
C. provides some characters of male plants to endosperm
D. all the above

Answer

**Step-by-Step Solution:**

1. **Understanding Double Fertilization**:
- Double fertilization is a unique process in flowering plants where two fertilization events occur within the embryo sac.

2. **Structure of the Embryo Sac**:
- The embryo sac contains several important structures:
- Three antipodal cells at one end.
- Two synergid cells and one ovum (egg cell) at the other end.
- A central cell that contains two polar nuclei.

3. **Pollen Grain and Pollen Tube**:
- When a pollen grain lands on the stigma of a flower, it germinates and forms a pollen tube that grows down into the ovule.

4. **Fertilization Events**:
- The pollen tube carries two male gametes:
- One male gamete fuses with the ovum to form the zygote.
- The other male gamete fuses with the two polar nuclei in the central cell to form the endosperm.

5. **Significance of Endosperm**:
- The endosperm provides nourishment to the developing zygote (embryo) as it grows. This is crucial for the embryo's development into a seed.

6. **Stimulus for Embryo Sac Development**:
- The process of double fertilization stimulates the embryo sac to develop into a seed. Without the fertilization events, the embryo sac would not mature.

7. **Conclusion**:
- The significance of double fertilization includes:
- Providing nourishment to the zygote through the formation of endosperm.
- Ensuring that the development of the embryo sac into a seed occurs only after fertilization.
- Contributing genetic material from the male gamete to the endosperm.

**Final Answer**: The significance of double fertilization is that it provides nourishment to the growing zygote through the formation of endosperm, ensures the embryo sac develops into a seed only after fertilization, and incorporates genetic material from the male plant into the endosperm.

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