Fertilization is
a)	Fission of sperm and ova
b)	Fusion of sperm and ova
c)	Zygote formation
d)	Gamete formation

(b)

Fusion of sperm and ova

Fertilization

The process of fusion of a sperm (male gamete) with an ovum (female gamete) is called fertilization

Steps

(i) During coitus, semen is released by the penis into the vagina (insemination)

(ii) The motile sperms swim rapidly through the cervix, enter into the uterus and reach the ampullary isthmic junction of the oviduct (site of fertilization)

(iii) A sperm comes in contact with the zona pellucida layer of the ovum and induces changes in the membrane to block the entry of additional sperms

(iv) The enzymes of the acrosome of sperm help to dissolve zona pellucida and plasma membrane of the ovum and sperm head is allowed to enter into the cytoplasm of the ovum, i.e., secondary oocyte

(v) Ultimately diploid zygote is produced by the fusion of a sperm and an ovum