Unlike other vertebrates, placental mammals and most bony fishes lack what?

Question

Animals which are ovoviviparous, such as some vipers and other snakes, frogs, toads, iguanas and lizards, sharks, and fish, do what?

Answer 1

A cloaca
In zoological anatomy, the cloaca is the posterior opening that serves as the only opening for the intestinal, reproductive, and urinary tracts. In placental mammals and most bony fishes the tracts have more than one opening.