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.
Material to diffuse is independent or dependent variable...
Answer:
The nucleus contains "the cell's genetic material, DNA." DNA makes protein molecules to help with almost every cellular process
Please said thanks
Carrying capacity is the number of organisms an ecosystem can support.
Answer: D).
