Some grow in an egg in their mother's stomach. Pups pop out through the opening in their mother's body. They are joined to their mother by a big cord that has a whole bunch of tiny cords that break as the pup leaves the mother's body. The sharks are then born live in the ocean. When the pup is born the mother leaves the pup on its own to take care of itself.
Some shark embryos get their food first from a yolk.
They use up all the food in the yolk. The yolk will turn into a placenta that attaches to the female's womb. Nutrients and oxygen from the mother then go to the placenta and through umbilical cord, so the shark embryo can grow. This shark gets its nutrients and oxygen from a yolk sac which is provided by the mother. This shark only needs one yolk sac.