(c) : By in vitro fertilization, the ovum is fertilized with sperm outside the body of a woman, providing the ovum with the same environmental conditions asit would have got inside the uterus. The zygote is grown inside a culture and when embryo is formed, it is then implanted into uterus where it develops into foetus and then into a child. This is called test tube baby. Methodology involves the following steps:Removal of unfertilised ovum from reproductive tract of a female. - Ovum is kept under aseptic conditions. - Fusion of sperm and ovum in a culture medium, outside the female body to form the zygote. - Zygote is stimulated to develop in vitro upto 32 -celled stage. - Developing embryo is implanted on the endometrium of the uterus at 32 -celled stage. So the pregnancy in the woman starts and further the development of the child continues in the womb till it is born.