Solution:

An animal that is viviparous gives birth to developed live young. The embryos are raised with special organs in the parents as they develop, that supply nutrients to the growing embryos. This condition is known as matrotrophy, when the embryo receives nutrients directly from the mother and not from the yolk. The difference between ovoviviparity and viviparity is that viviparous animals feed their embryos with nutrients from the mother. Without a large egg, there is no large yolk sac for the embryo to survive on.