Fertilization and implantation are the most critical events in the reproduction process. In this process, both egg and sperm are fused to form a zygote.
Later it gets implanted into the uterus and the development of an organism.
Implantation:
Implantation is the attachment of the developing embryo, moving as a blastocyst to the uterine wall and remaining attached to it until birth.
It takes place about seven days after fertilization.
The lining of the uterus (endometrium) prepares for the developing blastocyst to attach to it via many internal changes.
Fixing of developing zygote on the uterine wall Implantation.