What is double fertilisation?

Explanation

**Step-by-Step Solution:**

1. **Definition of Double Fertilization**: Double fertilization is a unique reproductive process that occurs in flowering plants (angiosperms). It is characterized by the fusion of one female gamete with two male gametes.

2. **Process of Double Fertilization**:
- During this process, one male gamete (sperm) fuses with the female gamete (egg cell) to form a zygote. This is the first fertilization event.
- The second male gamete fuses with two polar nuclei present in the embryo sac to form the triploid endosperm. This endosperm serves as a food reserve for the developing embryo.

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