I think the correct answer would be A. The yolk sac becomes the placenta. It is membranous sac that is attached to the embryo. It provides all the nutrition and the blood cells needed by the embryo. It is also called the umbilical vesicle.
Answer:
The flight feathers are known as remiges (wing feathers) and rectrices (tail feathers).
Terrestrial Ecosystem- Is a type of ecosystem found only on biomes.
Six primary terrestrial ecosystems exist: Tundra, Taiga, Temperate Deciduous Forest , Tropical Rain Forest, Grassland and Desert
It is the ovary i believe
hope it helps
The earths crust is broken into Teconic plates
