An event unique to angiosperms is

Options

A. Double fertilisation
B. Sexual reproduction
C. Pollination
D. Spore formation

Answer

**Step-by-Step Solution:**

1. **Understanding Angiosperms**: Angiosperms, also known as flowering plants, are characterized by the presence of flowers and seeds enclosed within a fruit. This distinguishes them from gymnosperms, which have naked seeds.

2. **Identifying Unique Events**: Among the various reproductive processes, we need to identify which event is unique to angiosperms. The options provided are double fertilization, sexual reproduction, pollination, and spore formation.

3. **Defining Double Fertilization**: Double fertilization is a specific process that occurs in angiosperms where two male gametes (from pollen grains) fertilize two different structures in the female gametophyte (embryo sac). One male gamete fertilizes the egg cell, forming a diploid zygote, while the other fuses with two polar nuclei to form triploid endosperm.

4. **Comparing with Other Processes**:
- **Sexual Reproduction**: This is a broader term that includes any reproductive process involving the fusion of gametes and is not unique to angiosperms.
- **Pollination**: This is the transfer of pollen from the male anther to the female stigma and is also not exclusive to angiosperms.
- **Spore Formation**: This is a method of asexual reproduction seen in other plant groups like ferns and mosses, and is not specific to angiosperms.

5. **Conclusion**: Based on the definitions and comparisons, the event that is unique to angiosperms is **double fertilization**.

**Final Answer**: The event unique to angiosperms is **double fertilization**.

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