In humans, the yolk sac in humans, the yolk sac is the site of origin for blood cells and primordial germ cells is no longer a useful structure forms the human urinary bladder passes nutrients to the embryo after digesting the yolk mass

In humans, the yolk sac is the site of origin for blood cells and primordial germ cells. The human yolk sac is a membrane located outside the embryo and it is connected by a tube through the umbilical opening to the embryo's midgut. The yolk sac serves as an early site for the formation of blood and in time, is incorporated into the primitive gut of the embryo.

cancer   is   essentially   uncontrolled   mitosis   of specialized cells

not: both offer magnification to the atomic level.