Marsupial mammals retain their embryos for only a short period in the uterus
Except for monotremes and marsupials all other mammals carry their babies in utero for the duration of their pregnancy.
A mammal embryo is the developing baby inside the mother.
The mammal embryo receives its nutrients from the mother through the placenta. The placenta allows nutrients to travel from the mother's system to the embryo's, and for waste products to leave the embryo's system so they can be disposed of by the mothers.
I believe it is called an embryo
Pig is classified as a placental mammal because it has placenta for internal development of its embryo.
Placenta through the process of diffusion
A placental mammal retains the young inside the body of the female and are born alive.
Monkeys are in the placental group of mammals which means that they have an internal placenta for development of embryo.
Mammal embryos don't require a large yolk becaues they are nourished directly by the mothers body. In contrast, birds, reptiles, and other (mostly) egg layers, need a large yolk because the yolk must nourish the embryo all the way through development.
Rabbit is a mammal which is pregnant for 21 days . Pregnancy is called gestation period in which embryonic development is completed .
Climate
fish
Yeti are not proven to exist, but if they did they would likely be mammals.