What is fertilisation?

Explanation

### Step-by-Step Solution:

1. **Definition of Fertilization**: Fertilization is defined as the process in which a male gamete (sperm) fuses with a female gamete (ovum).

2. **Nature of Gametes**: Both the sperm and ovum are haploid, meaning they each contain a single set of chromosomes (n). This is important because it ensures that when they fuse, the resulting zygote will have the correct diploid number of chromosomes.

3. **Formation of Gametes**: The haploid gametes are formed through a process called gametogenesis. This involves meiotic division of germ cells, where the chromosomal number is halved from diploid (2n) to haploid (n).

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