Placentals are mammals. All mammals are vertebrates which means they do have backbones.
Yes
yo kitchen lol
Yes.
No there is more with backbones
an ugly tsamanian devil
Monotremes, marsupials, and placentals
Pigs do have backbones.
No backbones
it has 2 backbones
All snakes have backbones.
Because placentals are the largest number of mammals.
all fishes have backbones