Kangaro ,Cat ,Dog, Goat , Horse , Elephant , And other mammals that develop inside the tummy of their parents . Its called Vivipary.
Vivipary has two different meanings.
In animals, it means development of the embryo inside the body of the mother, eventually leading to live birth, as opposed to laying eggs.
it means reproduction via embryos, such as buds, that develop from the
outset without interruption, as opposed to germinating externally from a seed.