What is the term for the fusion of gametes during reproduction?

The fusion of gametes during reproduction is referred to as fertilisation. This process involves the union of a male gamete (sperm) and a female gamete (egg), resulting in the formation of a zygote. Fertilisation is a crucial step in sexual reproduction as it mixes the genetic material from both parents, leading to genetic diversity in the offspring.

The other terms listed refer to different biological processes. Cleavage pertains to the series of rapid cell divisions that follow fertilisation, leading to the development of the embryo. Gametogenesis is the process through which gametes are produced through meiosis and other cellular changes. Segregation relates to the separation of alleles during gamete formation in accordance with Mendelian genetics, rather than the fusion of gametes. Thus, fertilisation is the appropriate term for the fusion of gametes during reproduction.