12 most iconic rivers on Earth. The Yangtze River's most famous sites include the incredible Three Gorges and the gargantuan Three Gorges Dam. There's a reason you know the names of these rivers--the Nile, the Mississippi, the Amazon--they've inspired exploration, legend, religion. Discover the waterways that shaped the world--and the cruises that reveal their secrets.
Illustration depicting ovulation and fertilization. Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the uterine tube. The result of this union is the production of a zygote cell, or fertilized egg, initiating prenatal development.Scientists discovered the dynamics of human fertilization in the nineteenth century.The process of fertilization involves a sperm fusing with an ovum.he result of this union is the production of a zygote cell, or fertilized egg, initiating prenatal development. Scientists discovered the dynamics of human fertilization in the nineteenth century. The process of fertilization involves a sperm fusing with an ovum.
It is by this adhesion that the foetus receives oxygen and nutrients from the mother to be able to grow. In humans, implantation of a fertilized ovum is most likely to occur about 9 days after ovulation, ranging between 6 and 12 days.t is by this adhesion that the foetus receives oxygen and nutrients from the mother to be able to grow. In humans, implantation of a fertilized ovum is most likely to occur about 9 days after ovulation, ranging between 6 and 12 days.