Which one of the following categories of animals is correctly described with no exception in it?

Explanation

All bony fishes do have four pairs of gills and an operculum on each side of their bodies. The operculum is a protective bony plate that covers and helps protect the delicate gill filaments. This arrangement allows bony fishes to extract oxygen from the water as it flows over their gills and to expel carbon dioxide. The heart is generally 3 chambered in reptiles but in the crocodile it is 4 chambered. Sponges are generally marine and have collared cells but few fresh water forms can also be seen like Spongilla. All mammals are viviparous (giving birth to young ones) with an oviparous (egg laying) exception: Ornithorhynchus (platypus).