Egg has several special extra-embryonic membranes, which allow it to develop on land independent of water ... Yolk sac is then infiltrated with a system of blood vessels, carrying nutrients from the ...

Egg has several special extra-embryonic membranes, which allow it to develop on land independent of water ... Yolk sac is then infiltrated with a system of blood vessels, carrying nutrients from the ...

Because the placenta is derived from the extraembryonic portion ... factor that determines whether an embryo will survive the deep freeze is the amount of membrane damage it incurs during the ...