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Do mammals develop in egg or in uterus?
Placental mammals and marsupials develop in a placenta within the uterus before being delivered. Monotremes develop in an egg.
Where do most mammals grow before they're born?
Most mammals are placental mammals: they develop in a placenta before birth. Marsupials also develop in a placenta, but they are delivered much earlier and the placenta is less developed. Monotremes develop within an egg, which is kept inside the mother for some time before it is laid. It hatches several days later.
Why can't humans lay eggs?
Humans are placental mammals, meaning that they develop with the embryo attached to a placenta that allows it to exchange waste and nutrients with the mother. The placenta would not be able to function inside an egg.
Do turtles have placenta?
No. Turtles lay eggs. Only mammals have a placenta.
Where do baby mammals develop?
I the mammal is a monotreme, it developes in an egg. If the mammal is in the marsupial group, it develops in a pouch on its mother. If it is a placental mammal, it develops in the placenta.
Does a squid have a placenta and an umbilical cord?
No, only mammals have a placenta with umbilical chord.
How do placentals young develop?
The young of placental mammals develop within a placenta. The placenta is a thick membrane that is connected to the inside of the uterine wall. The umbilical cord connects the baby to the inside wall of the placenta. Nutrients and oxygen go from the mother's blood stream through the placenta, down the umbilical cord, and into the baby. The baby releases waste products and carbon dioxide, which travel up the umbilical cord, through the placenta and into the mother's blood stream.
How do animals develop without a placenta?
Animals that do not develop in a placenta will develop outside of the uterus rather than in. Kangaroos and Koalas use pouches to develop their young.
How do birds develop without a placenta?
Placenta is used by certain mammals to nurture embryos that will develop into a baby that will be born live. Birds, however, don't give birth to live young. Instead, they lay eggs, and the embryo inside the egg is nurtured by a nutrient and energy rich yolk sac, rather than by a placenta.
Do dolphions have placenta?
Dolphins are mammals, give live birth, so also have a placenta.
How does a Stingray grow and develop?
A stingray is born alive, a fully developed but much smaller version of an adult. The mother holds the eggs inside of her while the babies develop and hatch, but is not connected to them through a placenta, as mammals are.
Do tuna have placenta?
No, tuna fish do not have placentas. The placenta is part of mammal physiology, and fish are not mammals.
